It's an easy way to help kids build decks. With self-contained archetypes, you can just put together a bunch of cards in that archetype and not worry about trawling through years and years of cards that may or may not help you.
It also makes it easier to sell packs. Archetypes let them put in a higher number of relevant cards into each set without power creeping too much.
That said, it does make deck building a bit boring. I enjoy deck building in Magic way more than in Yu-Gi-Oh. Magic takes the opposite approach, where the vast majority of cards are generic, and the deck building process benefits from it.
I'd agree with this in general but sometimes the sweetest thing in Yugioh can be finding a few generic cards or sometimes a squeezed in archetype that make your deck that much better, especially when it's an obscure choice.
For example, my Prediction Princess deck. Everyone knows at this point that Cyber Angels, Saffira, and Ritual Sanctuary boost the deck's speed and power, as well as Spirit of the Fall Wind being a nice way to search out your Pots of the Forbidden. Now, you could be boring about it and run 3s of everything, but my build is far more tweaked, due to Fall Wind's ability to search any Flip monster in the deck. So I trimmed my deck to two Pots, two Fall Winds, 1 Instant Fusion, and 2 Twin Twisters in order to squeeze in a few tech cards. Honest and Kristiya being run when you have Saffiras and Cyber Angel - Bentens isn't original on my part, but my choice of adding in four flip monsters is, IMO. As far as I can tell, people only really run Pots. My four one-ofs are:
-Magician Faith
-DUCKER Mobile Cannon
-Scapeghost
-Dummy Golem
Magician of Faith lets me get into Shenanigans(tm). It lets me recycle spells like Raigeki, Instant Fusion, Twin Twisters, and Preparation of Rites to use them multiple times per duel at best, at worst gives me more fodder to pitch with Ritual Sanctuary to enable a play. Topdecking it has legitimately saved my bacon at times, while going into it via search usually means I can lock my opponent between Pot's multiple disruption abilities, Taraotrei's once per turn Book of Moon effect, and Magician of Faith to continuously recycle obnoxious cards like Twin Twister and Preparation of Rites to tighten the noose around my opponent and ruin their resources. Add in the usual Honest in hand and Hymn of Light in my graveyard and it's a lock that usually leads to opponents surrendering.
DUCKER can recycle any Lv 4 monster to my hand; if I'm in a comfortable position in a duel, I'll search DUCKER first so that I can loop it and Taraotrei to bring out my other toolbox Flip monsters, or recycle Manjus for two or even three searches per turn. Topdecking or drawing into it is rarely bad, as worst-case scenario if you brick it'll let you recycle either Manju or Fall Wind enough that you can start making power plays.
Dummy Golem is my out to obnoxious boss monsters like Apoqliphort Towers and its various untargettable or unaffected clones such as the Raidraptors rank 12 boss and Dank Destroyer. It's the tech card most likely to brick my hand but in a worst-case scenario it'll force an opponent to give me one of their beefier monsters; Burning Abyss in particular dislikes doing so as most of their beaters are 2500 beaters.
Scapeghost is there because it can easily stall in a pinch at worst, and at best enables me to make Synchro plays that either stop my opponent cold or let me attack for game worry-free; running Taraotrei means that Leo, Keeper of the Sacred Tree and Star Eater are easily dropped, as well as letting me go into more control-oriented Synchros like Trishula and Psy-Frame Omega when combined with Saffira or Manju/Fall Wind.
Innovation isn't dead per se, it's just that some of the most useful cards can also be incredibly obscure to most players nowadays. 3 of my tech cards are actually fairly old, and other techs I considered such as Spear Cretin, Hade-Hane, Magical Merchant, and Buten also fall under 'old, good, and rather obscure' for this specific deck.
