State-based animations are "future proof".
Check this video of a combo in the new Spiderman 2 game. Does any of this look cool to you? To me it looks like visual gibberish with messy state transitions, unfinished animations that make the player look like they're in stasis, Suck To Target mechanics that mess with the flow of movement (0:14) and all kinds of similarly unpleasant crap. Why does high level gameplay look like this? Clearly it had the budget, it had the talent, it had the skill.
My guess is that the obsession with interpolation of all kinds (with the end goal being realism), reliance on automated algorithms, the complexity of animations, lack of harmony between gameplay programmers & animators is what lead to this.
Interpolation in animation is essentially the computer guessing the trajectory of an object based on its starting and ending position, with some extra constraints. It has almost always been a thing in games (and code-based animation is a type of interpolation) but its use has been fairly limited. Now interpolation is everywhere, nearly every state transition needs extra frames where characters move into the next key pose, different limbs have different algorithms even (such as matching foot position to terrain), everything is very complicated and automated.
This is fine in slower games that are entirely centered around their animations - where you can't interrupt or cancel any states. However, where this starts to completely fall apart is in fast paced, player input driven games. There, the developers either have to use hacks to prevent players from getting too crazy with the cancels, or keep the interpolations and still match what the player is doing but gradually, slowly.
As a result, high level cancel-based play is increasingly starting to look and feel like the characters being completely incapable of keeping up with your inputs. Before they even fully start swinging, they need to already be in a completely different state. Sometimes the characters get locked into a kind of "averaged out" animation because they simply won't have the time to get to their cool key poses. These unpredictable state transitions can be chaotic as well, so the interpolated animations tend to look bizarre to say the least.
Adding to this issue are the Suck To Target mechanics where the player gets magnetized to enemies after pressing inputs. These abominable mechanics completely ruin the momentum of different animations - how am I supposed to feel any sense of forward or upward momentum if my character can just instantly slide left or right on a whim?
In older games (think Ninja Gaiden & DMC), the animations were tied a lot closer to states, so any state transitions would be clearly represented by sudden key pose changes (and probably VFX too!). While this might look a little weird, its value as instant feedback for the player's actions is hard to deny. The characters no longer struggle to keep up, they are in complete harmony with your inputs. As a result, the animation scaled well with the player's skill - they would look snappy at lower levels, and would look just as snappy if not more at higher ones. They also didn't have such excessive Suck To Target or assist systems, so every animation & state combo was, dare I say, bespoke in its function. It was beautiful.
Shoutouts to Nioh for kiiinda getting around this issue with bright flashes during cancels.
