[heracles]

That is a fair point, but isn't it built into this particular field?

We can prosecute equally for jaywalking, but anti-competitive behavior gets worse the bigger the offender is and/or the worse offense they commit. So in that way it makes sense to prosecute "top-down", that is go after the biggest ones first.

That's at least what I prefer as an EU member state citizen and consumer.

[azernik]

Not only does it get worse the bigger the offender is; in law, generally there are specific actions that you're not allowed to take iff you're dominant in the market.