If anything, EU would create a generic fund to subsidize any such investment coming from any company interested, but at EU level, it would definitely take time.
Or they can talk to individual countries about subsidies, just like they do with the US. Plenty of them can afford it.
While other US states encourage their own tech centers' growth, Floridians and New Yorkers and Texans are all aware of, benefit from, and are proud of Silicon Valley being in the US.
In my opinion Europe needs to go about it via policy, and maybe even culture, rather than funding. Get rid of non-competes. Make financing less scary for founders and make bankruptcy less punishing - my understanding is that in the EU, a startup failing can destroy a founder's life financially. Controversially, roll back overly permissive or complex labor laws that make it difficult to fire and hire.
None of this involves throwing money at the problem. It's about incentives. There's little reason for someone who wants to grow a large technology company to do it in the EU. There's little reason for someone who wants to be an employee of a startup to do it in the EU either. Obviously people still do both, but it's at too low of a rate and density for it to sustain a chain reaction leading to something like SV.
It's what happens when you redirect so much money to politicians and bureaucrats. Creating jobs is how they get reelected. That's also how you get labor laws that make it difficult to fire and hire: the slacker's vote is worth just as much as the startup founder's.