The fact is that cloud is expensive, and outside a few use cases (such as extreme horizontal scalability, aka elasticity, or machine learning) the costs just don't work out well.
And then of course every "cloud" is full of about a billion hidden gotchas ("well the marketing page says that'll work, but on Tuesdays in February it won't, so use this instead, but only if you're writing your logic in JavaScript because the tools for the other allegedly-supported SDKs are broken in weird ways half the time, so instead use this other thing, unless you're a Libra, then...") none of which knowledge transfers between "clouds", and each has a pile of dumb names to memorize and a ton of other per se useless, but necessary, knowledge you've gotta pick up, just to rub salt in the wound.