As others mentioned, throttling your settings will show you that the differences actually aren't that negligible. With the Chrome devtools, throttling network connections to Regular 3G and CPU slowdown to 10X will give you a rough estimate of how mobile devices with flaky connection interact with these applications.
Another thing is that each of these implementations pre-cache most (if not all) of their static resources with a service worker -> and that's why repeat visits on each site is quite fast. Using incognito or clearing the site data and unregistering the service worker and then loading the site as a first-time visit under those throttled conditions will let you easily notice how much faster some of the implementations are then others (for example: Preact and Angular)
Another thing is that each of these implementations pre-cache most (if not all) of their static resources with a service worker -> and that's why repeat visits on each site is quite fast. Using incognito or clearing the site data and unregistering the service worker and then loading the site as a first-time visit under those throttled conditions will let you easily notice how much faster some of the implementations are then others (for example: Preact and Angular)