I both agree and disagree with this take.
I started out hand-coding static html pages, graduated to Drupal and Wordpress php stuff circa 2009 (glad that's over!), then worked on a largely server-rendered Rails SAAS in the APM space that I guarantee you've interacted with if you've been in the web game for more than a couple years. These days, I may sling React for my 9-5 but a lot of my personal projects and internal tools are vanilla express apps with very little client-side code.
It's true that a lot of newer devs really don't have a great deal of context for why React & company became the de facto default for building websites and how much we used to get done with largely server-based architectures. I wish we did a better job of teaching fundamentals here rather than bootcamping everyone straight into building SPAs.
However, it's also true that the baseline expectation for web experiences is a lot higher in 2022 than it was in 2009 in terms of the level of responsiveness, interactivity, and overall "app-like-ness", to the point where I think that even with the massive improvements in bandwidth, latency, and web protocols, we still need to accept that there are many cases where just shoving full HTML documents over the wire isn't enough to satisfy user & stakeholder expectations. That's where stuff like LiveView, htmx, and Web Components become interesting to me. The web has evolved, and finally the server-side-application paradigm feels like it's starting to evolve along with it, and these evolutions do feel like they're novel & useful enough to deserve being called "new ideas".