Web Assembly could help given devs won't need to rely on external frameworks (which do slow things down considerably). Your spot on about HTTP2 though, it just streams the files. There should be metadata in the HTTP request object that signifies the device properties and an appropriate response is given for that device's specifications.
I 100% agree with you - but navigation is way harder on a phone browser than with a mouse. Also mobile having way less memory capabilities slows down browsers a tonne when web developers make content decisions based on what will cache quickly and easily on their 2000 dollar iMac.
If you accept that then you've missed the broader point. Not a single founder would want their idea to appear on next years board of stupid ideas to satirise.
Is this not the gratuitous negativity that Hacker News seeks to avoid? Satire is not universally good. Many start-ups in their infancy could be classified using that list. Indeed many of those start-up's founders come here for resources or support.