In 2014, when this was originally written, I'd totally agree - but it was 4.5 years ago and a lot of things have changed in the meantime. At the moment I'm dealing with one jQuery old-school project and while on one hand it's really a nice feeling to debug code without constantly waiting for webpack to finish compiling the code, most of the time I'm really in pain. After years of working in Vue and React it just feels ugly and messy and it's much more complicated to understand and refactor. To quote on one of my fav Stephen King's books "the world has moved on" since then...
It's been probably 2 years since I've seen a front-end dev listing that doesn't list experience with a SPA framework as mandatory. I'm not going to question that hybrid and traditional apps exist in the wild. I maintain some myself. That being said, I think it's pretty clear that at the very least the world is moving on. We are asking for more out of the web than what it was designed for, and it's difficult to meet the expectations of modern users without modern tooling.
By way of example, I do a lot of freelancing and have quite a lot of clients that I think would be better served by a traditional web app (much faster to develop, though not nearly as rich interactions dollar for dollar. Also a lower infra bill generally.) Many of them refuse though because they've been conditioned to expect the kinds of features that SPA's provide.
I write a lot of business automation sorts of apps for SMBs. Something I see requested a lot is wizard style workflows (on a web app.) This is trivial in a SPA and a major annoyance at best in the context of a traditional app framework. I totally agree that the world might not have moved on yet, but I think it's pretty clear which way the wind is blowing. Users are expecting rich SPA interactions as the new normal.
I didn't mean to say that SPAs were easier at all. They're not. I think they're under most circumstances much harder than traditional webapps. That being said, my experience is that users and in my case clients are starting to expect SPA features and it's harder to try and coax extensive SPA functionality out of a traditional web app than it is to just write a SPA.
I suppose it's all relative, but at least in Rails, while I suppose it's trivial in an absolute sense, it's much harder than doing stuff "the rails way."
