Most of this tech has strong network effects. And while the marginal cost of shipping an additional unit tends to be close to 0 (creating the incentive to grow almost boundlessly), the costs of complying with regulation in dozens or a hundred countries is quite high.
Thus, it entirely makes sense for a founder want to build great tech and a great product, but NOT want to be in the business of complying with a dizzying array of local and international regulations, in a world where they effectively have to expand globally to "win".
Big companies aren't typically nimble enough to respond to the whims of consumer tastes or catch the latest fads.
So, it's a great symbiotic relationship between "big tech" and startups.
Acquisition, cash out, bolt on regulatory and legal framework, wash, rinse, repeat.