I think there's a catch when it goes to expecting VNs to progress on a technical level... 2D art does not scale to technological capabilities the same way 3d graphics do, and VNs are way past the era of technical limitations of computers/consoles being the thing keeping them down in any way (unlike visual media that struggled with those for many decades). You say better sprites... But what can you do to make them better outside of working your artists to the ground? More animation? Upscaling by neural networks? These will always be controversial, to say the least. Better engines, but how much can you really streamline stuff with meaningful gains when 2D art and text are still two core elements of the experience? As long as VNs are the medium they are, there are pretty hard limits to how they can evolve when it goes to form. I mean, remember that VR JVN Sekai Project helped to crowdfund and localize? It was different... But kind of pointless, because VN formula at its core has little use for such gimmicks.
When it goes to tropes, story quality and generally getting closer to their full potential... Hard to say. Eroge scene is extremely stale right now. EVNs are in a particularly non-lucrative corner of the already-struggling indie market and are growing rather slowly. I'll have to see real change before I believe in it... But also, my near-infinite backlog and similarily gargantuan Steam wishlist suggest that we're getting enough cool things to read even as it is.