Your examples are mostly trash, but the right answer is circa 04-18, with 04 being the EARLY beginnings of anime peaking. Nanoha is a very rough and early example, but it signals a change within the audience: Cute things are fun. And fun things can be engaging in so many ways, including emotional, violent, tragic and so on. Essentially, in my opinion, this is when "moe" gets charged up to a 1000%, for the benefit of all mankind I might add. It's this very shift what arguably made anime as big as it is today, with heavily influencing other genres of entertainment.
So next you get a lot of stuff like Fate/Stay Night (yes the deen adaptation is trash, it still goes to my point) and a lot of other (to this day) popular VN adaptations like all the KEY crap (Clannad, Little Busters...) which, among other things, led to Kyoani making K-On, which is kinda the culmination of my earlier point. It's cute (and moe) to a peak, and it's probably one of the best things mankind ever created.
So the industry is in full force now. We have legit 10/10 masterpieces like OreImo, Monogatari and others which then bleed from the aughts into the 10s. It probably peaked with Madoka in 2011. We're riding this peak for a couple of years, like up until 2016 I'd say. Monogatari was coming around it's last season, there was still amazing stuff out there (Re:Zero, Shinsekai Yori, Hibike, Chuunibyo, Tamako, Mouretsu Pirates, imas, AKB0048, Macross Frontier, Rinne no Lagrange and like 200 more) but then imo it kinda slowed down.
Keep in mind all of these shows are VERY different in their approach to almost everything compared to most of the shows from earlier days. And yes, obviously it's easy to dismiss this as being something for lonely guys with waifu dakimakura, but this would be a really simple way of looking at it. We complain all the time about stories not being original or clever or whatever; Because they can't fucking be all the time lmao. How many "ports" of Shakespeare works won oscars and were released to critical and public acclaim? What, like Quentin Tarantino movies (which I LOVE) are known for their riveting plot? It's about characters. You need to write characters that appeal to people (best case so much so that they buy fucking body pillows of these, you bet your ass Sony would just love to sell you a Madam Webb daki), which is much easier said that done. It's not like you slap a pair of tits on someone and call it a day, otherwise I'd be a prodigiy of a mangaka or write LNs all day.
If you somehow manage to make your audience give a shit about your character (engaging written dialogue/personality often works) you're then well set up to tell whatever story you want, even if it's fucking romeo and juliette again, or just some violence revenge thing. Doesn't matter. Anime kinda min/maxxed this. Take Nisekoi. Nothing about that is original lmao, but it doesn't need to be.
I get that some people like to complain about this, but these people just need to be kept behind a fucking gate. There's a very organic and based reason moe was charged up the way it was. People love it, rightfully so. It was (mostly) always a somewhat heavy part of anime, because the cultured creators and audience alike enjoy this stuff.
Sure moe gets cheaply exploited, but what doesn't. It's plain silly to complain that we don't get "any good" anime anymore because it's all moe trash or moeblob or something
Frieren and Mushoku Tensei both are examples of recent anime that still adhere to moe as their #1 dogma but are both 9/10 shows.
So overall I'd say 06-16, since you asked for 10 years, and I'd call it "The Rise of KyoAni and its impact on the world of entertainment".
It's not like anime is worse now, but just like many other forms of entertainment it's under different constrations now. You need to do good on Crunchycroll now, on TikTok with a braindead Gen-Z audience, VISA is blocking payments in japan for content they deem "inappropriate" and companies like KADOKAWA (and all the others, they all suck besides of Kyoani and Shaft and some others) are more profit driven than ever. So pretty much like with hollywood/netflix and any other production.
