I mean there's a perfectly rational possible explanation for this - if the fines are actually just an extra targeted tax on these companies (but it's politically inconvenient to just do it honestly by levying a tax), and they would therefore adjust the laws to make sure they could still fine them if they had already complied...

May be that the people in charge in the EU don't really care about the market dominance as long as they can collect enough extra money from them...