Presenting in terms of marketshare is maybe not the best metric. My understanding is that the EU motivation here isn't so much the chips themselves as is it a stable supply chain for industries that rely on said chips.

It might be better to measure what percentage of existing EU "critical demand", for some definition of "critical demand", can be met domestically.

That is, the EU's goal probably isn't "become the dominant player in the chip market" so much as "don't permit problems abroad to knock out critical EU industry". It probably is not the case that they need to have a large percentage of absolute marketshare to achieve that goal.

I'd also add that the US is subsidizing several fabs for what sounds like similar reasons.