Saying they're fast is a relative statement. I primarily use an MNT Reform. On 4x ARM Cortex-A53 cores, most modern web apps are slow (the new reddit interface, the new gmail, virtually every airline booking UI, my music player of choice, etc.). I hate the web.
Reddit is just written s**tty. It is the worst case you can use to recommend react to peoples. Their desktop version is even worse. It eats a whole core of r7 2700x for 1 seconds just to update vote counters on page.
Do you believe that these sites would be fast if built with other non-SPA or non-“modern” libraries?
It’s like thinking that a faster car or a bicycle could be faster in a city with bad traffic light logistics. All of Svelte, React, Vue, jQuery, DOM are equally visibly fast until you attach these 10 megabytes of /metrics-n-spyware/**/*.js.