Remember when the web was just a bunch of static HTML pages with terrible backgrounds and the occasional animated GIF? Those days are long gone.
Your browser does more than it ever has before. This is how computers have always worked. If you want the features they offer, you have to be willing to give up some of your precious resources for the features that make your life more convenient. Using any extensions on top of that? They’ll eat up even more RAM. Extensions add even more features to an already feature-rich browser.