Yes, and it's also because a 2 KB text today comes inside of megabytes of code that has to be executed, and some code is additionally very expensive to execute,

Yes, and it's also because a 2 KB text today comes inside of megabytes of code that has to be executed, and some code is additionally very expensive to execute, as it's doing shady stuff in trying to fulfill all the promises of all ad companies involved, sometimes really hundreds for a single page. There was a moment in web history when the same happened due to the flash-based ads which easily spent huge amounts of CPU for... nothing meaningful to the reader. Now the flash is gone, but the pattern repeated. And even not counting all the ads, today's "hot" web development conventions are often making the CPU even hotter.