No, they are not becoming irrelevant. Frameworks add significant value on the front end as well -- the easiest example is templating, which is a) not natively supported in HTML b) hard to fake with CSS/Javascript and c) virtually required for productivity, consistency, and maintainability.
I suppose one could theoretically fake this by using a script to spit out static HTML served by Apache, but then the combination of Apache and your script is morally equivalent to a server-side web framework.
I suppose one could theoretically fake this by using a script to spit out static HTML served by Apache, but then the combination of Apache and your script is morally equivalent to a server-side web framework.
Session management. Cookies. Sitewide functionality. Asset packing. SSL. Debugging/development tools. Tests. etc, etc, etc, etc