Time is an issue. But money is also an issue. That's partly why digital is a thing: it saves some time and some money, but it's just plain in general. Money buys good talent. Although I hate it, compare Kill La Kill to other anime digital TV series. Despite being digital, it LOOKS just like high end cel. They put in time, but they also have some of the best talent in the industry and have amassed a pretty small fortune. Time, talent, and money all factor into animation. But even back in the day, when Sailor Moon reused those transformation animations, it still had a massive amount of heart out into its shots. Sailor Moon was no GitS:SAC in terms of animation, but it still looked good. Besides being a popular brand, it made Toei money because they were frugal with it. And yet, it still looked amazing and had to worry about going ahead of the manga. Sailor Moon's new TV series has had all the time in the world to look good. So did FMA: Brotherhood. They're both based off finished manga stories. In the case of Ssilor Moon, the manga finished almost 20 year ago? So it's no excuse.
Essentially, digital saves time and money, making studios like Toei who don't give a fuck, half ass on it. Then you get stuff like the new Sailor Moon.
Furthermore, Japan's animation industry has had a mass talent exodus. There's not nearly as much talented worked in it as there were say, twenty years ago. So for a lot of projects, all three are lacking.
A) When I say time, I mean literally the amount of time the animators have to make an episode or series. It takes weeks to make a single episode of anime (though of course they are working on more than one episode at a time on a staggered schedule). When you have to make a new episode of a show every week for 6, 12 or more months at a time, its very hard to devote the maximum allotment of time to making a show look its absolute best. Your lead time tends to shrink as you move forward and deadlines get tighter. Just because something is an adaptation of a product from years back doesn't mean the production schedule is going to be great. Some studios/animators are allowed to take 1+ years on a project and others have to pump out a show in months. That time difference matters a lot.
With regards to
Studio Trigger, they have talent (Imaishi, Yoshinari and Sushio among others) but I would not call them a rich studio overall. When their production schedule goes to shit you get stuff like
Kill la Kill. When their production schedule is more open/flexible you get
Little Witch Academia. That they imbue a lot of their products with a sense of style is more to personal discretion and the character designers they use. It also seems to be more focused on their original IPs (
Kill la Kill, Little Witch Academia, Kiavnizer, etc.) and less so their "for hire" work (Superpowered Battles are so Common or whatever the name of that show was).
In another example of how important production schedules are, I mention
Studio WIT. When
Attack on Titan was actually animated it often looked incredible. However half the time you'd be getting a slideshow. Why? Because their production schedule was so borked that they could barely deliver episodes finished to air on TV. It wasn't like all their animators forgot how to draw all of a sudden and it wasn't money as they were paying money out the ass to get enough animation directors to finish the episodes (when you look at the credits of an episode of anime and see 4242125 animation directors, something usually went wrong or there was some MAJOR crunch).
Rolling Girls was another recent example where the animators were even complaining about the production schedule on Twitter (of course they had to rapidly delete said tweets once even people in the West were catching on LOL). The first few episodes of that show looked AMAZING but the later set, bar some exceptions, were much worse.
Kyoto Animation is one of the most prolific animation studios in Japan nowadays. A lot of the shows they make are lacking in substance or writing quality but they often look AMAZING and that's thanks to their superlative work environment and production schedule. They work on very few things at a time and they don't need to rely on freelancers like most other studios.
Ufotable is generally the same way (though
God Eater ended up being an unusual clusterfuck).
Madhouse (and
MAPPA to a lesser degree) and
BONES have a good reputation for following consistent production schedules. Its' part of the reason Hunter x Hunter 2011 was such a consistent looking show (from what I've heard and the bits I've seen) or why BONES consistently puts out such stylistic and good looking shows. Money and Talent asre super impotant but production schedules and how different studios manage them (or how individual project mangers handle them) are also extremely predictive of the quality of animation a show will have (more so than money I feel). I feel people often underestimate this.
Oh and on one more note, Toei is a piece of shit. They hire slave labor from the Philippines and follow terrible production schedules for like all their shows (of which they make like 325613251325 at a time) with the EXCEPTION of the
Precure franchise? Have you watched that (or even just excerpts and gifs)? That shit looks GREAT most of the time. I wouldn't use Toei as an example to condemn digital production as a whole.
As an aside, a big reason that recent
Dragon Ball Super episodes have looked better is because World Trigger and a bunch of One Piece specials just ended which freed up more animators to actually work on Super. I hope it keeps up.
B) Mass talent exodus? I'm not seeing it at all when it comes to animation. Yes Studio Ghibli cratering sucks, yes the death of Kon was devastating. The increasing proliferation of webgen animation and hard work on display by the mixture of newcomers and the old guard tells me anime is perfectly fine from an animation standpoint.
Yuasa, Hosada, Natsume, Yutapon, Kameda, Obari, Nakamura, Bahi JD, Ryo-timo, etc. are still putting in God's work. How much recent anime are you watching? If you're looking for visual spectacle, its out there.
In a visual medium like animation, I wouldn't exactly say "this doesn't look good" is exactly nitpicking.
The issue is that literally every show ever animated has a non-zero number of still frames that look less than ideal when pulled out of context. You can't post a screenshot of a random show and say "LOL bad animation" and have it mean much. You need to provide video and said video has to be representative of the show and not an exception.
EDIT: Though to be fair, the discussion or character art/background art is different than a discussion of actual animation. I've seen too many people conflate the two for my tastes so maybe I'm off base on the actual intentions of Fawful.