You're skipping a lot of what made those companies happen.

Google was actually good once. They had a clean, usable website in an era of pop-ups and overused animated GIFS. Also, their search actually worked. They also had a bunch of cool programs and tools that they've since killed.

Facebook was also sort of good. But not really. Most of that was a sort of first mover advantage. Myspace existed, but didn't catch on, and then Facebook comes along, and it has a bunch of free games (that steal all your data). Since Facebook was most people's first social media, and their family's first social media, they get locked in.

Bill Gates' Mom was on the board of directors at IBM and forced the company to use her son's OS.