I won't of course argue that new hardware will be considerably faster, but people vastly overestimate the base level that's actually required to run your basic game that uses a framework which wasn't built to rely on the newest, shiniest whistles. (or alternatively, underestimate the level of power they already had at their disposal a decade ago)
I hate those lazy devs to the core for using tech advancements as an excuse to not-optimizing...
Is this absolutely dogshit setup?
Yes.
Should it have any issues with playing any ADV VN?
NOT A SINGLE ONE
Those dudes get their hands on a fully completed engine, all they have to do is add own pngs/webms/Live2D, add script, and...
I guess that's it. 2 steps to make the game run perfectly fine for everyone involved.
And yet, they decide to go extra miles just to make it worse xD
Now that I wrote that, it's even worse than being lazy, it's being malicious.