Yeah, I came to about the same conclusion not long ago when reviewing the latest crop of frameworks at TodoMVC.com while looking for the "best" way to build new apps.
I ended up not being able to conclude what was "best" so I decided to look for the "easiest" way instead. That was a lot easier because it's a fluid approach.
While I appreciate the goals of a single page app I would never make that a requirement when designing one. I'll use it where it easily works and not when it doesn't.
There are countless ways to make an app but in the end productivity is what gets it shipped and pays the bills and the easiest way is almost always the most productive.
Right now jQuery and Bootstrap are probably the easiest way to build a front end and unless you really need something more it's hard to argue against not using them if productivity is accounted for.
That, of course, will vary with one's own experience. If you've spent the time learning how to use React or Angular you might be more productive with that, but I'm thinking probably not, or not much, in most cases. What you really may be doing is addressing efficiency issues and other problems you don't have, and possibly adding unnecessary complexity.
If your app ever gets to where it doesn't work for you because you have so many users it needs to be more efficient, then good for you, you've hit the big time and should invest in efficiencies appropriate to scale, but you may find that's not a problem, or not where the problem resides.
Software is no different than anything else when it comes to applying the "KISS" approach and the more complex the project the more important that becomes.