It's not a stupid question.
First of all, none of the GAFA were actually started as Cloud infrastructure providers.
So the question is not why isn't Europe creating big Cloud Infrastructure companies, one could argue that the biggest "pure-player" in Cloud is OVH which is European.
If anything it's the (insanely lax and pro-monopoly) American regulatory environment that has the biggest impact on the creation of big Cloud providers outside of the U.S.
The only country that manage tyo do that are China & Russia to a lesser extent because they have active protection against AWS/GCP/MS.
As to why Europe doesn't create big GAFA-like companies in other sectors, one reason is that the E.U is not a single market from the perspective of these companies.
Yes the regulatory environment is stable & simple enough for companies to operate in all E.U countries, but that's not all that makes a market.
The fact that europeans speak 27 different languages for instance makes building a european sized company much harder than a U.S sized one, for roughly the same market in terms of $$$.
EDIT: I don't think creating GAFA-style companies is a goal any state should pursue.
The U.S needs to get their head out of their ass and split AMZN & Google ASAP, & fix Facebook.