your point has a truth behind it for sure, but there's a large difference between serving requests and making requests. Many sites are simple html and css pages, but many others also have complex backends. It's those that often are hard to scale and why the cloud is hugely popular, maintaining and scaling the backend is hard
I found that my local system could easily handle 512 parallel processes, with my CPU @ ~35% utilization, 2GB of RAM usage, and a constant 1.5MB down on the network.
Another thing that happened in the early web days was Apache. People needed a web server and it did the job correctly. Nobody ever really noticed that it had terrible performance, so early on infrastructure went to multiple servers and load balancers and all that jazz. Now with nginx, fast multi-core, and speedy networks even at home, it's possible to run sites with a hundred thousand users a day at home on a laptop. Not that you'd really want to do exactly that but it could be done.
Because of this I think an alternative to github would be open source projects hosted on peoples home machines. CI/CD might require distributing work to those with the right hardware variants though.
