On the market end - Google got huge because they inserted themselves as a critical part of peoples' usage of a resource that got even huger.
As late as 2013, my coworkers and I would mock the Wall Street analysts who covered Google because (you could tell from their questions on the earnings call) they assumed that the Internet was no longer growing. So all the focus was on CPCs and Google's ability to monetize, when the number of queries had quadrupled over the previous 4 years. You can hold monetization absolutely constant and if usage is growing 400%, your revenue will grow 400%.
Just two days ago Google's earnings came out and people were wondering how they still managed 20% YoY growth. Some of that undoubtedly came from Cloud & other emerging businesses, but I'd bet that the Internet is still growing.
CoinBase is trying to pull off the same thing with crypto - they're a critical onramp for people wanting to get started with a new, fast-growing technology. Regulators & the press always fight the last war, though - they're focused on Google and Facebook rather than on the next wave of giant monopolies.
People always underestimate the potential size of consumer markets, because their perspective is human-centric. Before they & their friends adopt a new technology, it's a toy or a fad and will never catch on. Afterwards, everybody they know already uses it, so of course it's old news. Few people realize that "everybody they know" is less than one millionth of all of humanity, or that if you're in a developed country you will get innovations 10-20 years before the rest of the world does, or that if you're in a tech metropolis in a developed country you will get them ~5 years before the rest of the country. "The future is here, it's just unevenly distributed."