To be clear, this is something I'm mulling over, not a hard conclusion, but here it goes...
Creating a simple, server rendered, text based web site may be exactly what the users need, but from a developer's point of view, it can also be a career risk. A rapidly increasing percentage of development jobs out there now require experience with a front-end framework. As a result, developers need this experience, so they start adding front end frameworks in order to 1) gain that experience, and 2) document that experience in a real world project. Remember, a project isn't just a project, it's an audition for your next project. This is how tech recruiting works[1]. So developers may be adding new bells and whistles that are not only unnecessary[2], but actively harmful to their current project, largely because they are necessary to their resume, and it's actively harmful not to have them there.
In short, one of the reasons the web is becoming unreadable is that web developers can't create the resume they'll need for their next gig by using the best tech for their current one.
[1] I'm getting long in the tooth enough to have seen this a few times. Companies required "EJB", it wasn't enough to have experience with Tomcat and standard Java. Later, Spring, Struts, Hibernate, iBatis were required. These days, it's ember, react, and other rapidly evolving JS frameworks.
[2] I want to be clear that I think many of these frameworks are actually pretty excellent, for projects that need them. The problem is, if your current project doesn't, you still have a strong incentive to bring them in.