That's an interesting assertion you make there about opinionated frameworks. Do you have a source for that? From my perspective, opinionated frameworks have only gotten more popular. Rails might not be the darling of every startup in existence anymore but I think that's largely down to other languages coming in and adopting the best parts of Rails and crafting their own flavor that plays to the strengths of their favorite programming language. Django, Laravel, Spring Boot, Blazor, Phoenix, etc etc.
While a lot of people here on this platform like to tinker and are often jumping to a new thing, most of my colleagues have no such ideas of grandeur and just want something that works. Rails and it's acolytes work really well. I'm curious to know what popular frameworks you're referencing that don't fit into this Rails-like mold?
I'm not familiar with all frameworks you listed, but i've worked extensively with spring boot and i can assert you that it's not a opinionated framework (as in one way how to do things correctly). Blazor and Phoenix are niche frameworks that don't have wide adoption outside this site. Django has a shared history/competition with Rails but it's also not widely popular.
> We take an opinionated view of the Spring platform and third-party libraries so you can get started with minimum fuss
Spring Boot is definitely opinionated (this is taken from their home page). Maybe not as much as RoR, but saying it isn't at all sounds very strange to me, having worked with it for a few years too...
> Django has a shared history/competition with Rails but it's also not widely popular.
Are you sure? Django is insanely popular. I am not sure on what basis you are saying Django isn't popular. I posit Django is more popular than Ruby on Rails.
Django is super popular.