Have the people who complain about javascript page load performance read about netflix.com? Netflix uses JS to render their landing page server side. No client JS necessary. How can a page load faster than raw HTML?
You do realise that Netflix doesn't need to depend-on/load adverts and mass tracking scripts and given the company itself is tech based their sales doesn't get the mighty power to force their devs inserting x40 tracking/adverts scripts and annoying popups? P.S. Netflix does ~17 ajax calls immediately after loading to hydrate its SSRd page ;)