Can't help but notice that we keep wanting to make content that should be flat more 3D (e.g., animated 3D backgrounds, scroll filler on corporate pages, the entire metaverse), and content that could benefit from being 3D more flat (like UI buttons losing their pseudo-3D bevels and not looking like interactive widgets at all).
Re UI, my theory is that this is partly because minimalism doesn't become dated as fast. Related, I remember that what blew me away upon seeing the 3DS for the first time was not the 3d playfield (which looked exactly as I expected), but the UI in 3D. It really felt like a glimpse into an exciting future.
Minimalism is a very easy style to pull off because the fewer elements there are the easier it is to make them all consistent, uniform, simple. It takes the least time to get it right. It can be handed off to someone else without explaining any "vision" or guidelines.
None of this is to say it is bad. Minimalism is good actually. Just that minimalism isn't uniquely good. Other designs can be timeless, they just rarely are.