Let's forget Europe and let's focus on the US market alone.
If we do the math, we have to ask - where would those 20 billion dollars come from that were to be paid by Adobe to Figma investors? I'm sure not from Adobe's coffers, their bean counters would place them onto subscription pricing with a time cap to recoup all that cost. For sure.
I would assume that regulators aren't unaware of that in the said markets (UK/Europe) and are not pro investor (few hundreds) rather pro consumers (millions)