How do we fight that ?
I'm thinking on this topic a lot lately - how do we change the system so that the bigger the company, the harder it becomes ? It's more of a political / societal issue. Similarly to housing - I believe it should be cheap to buy your first home, more expensive to buy a second one, and very expensive afterwards.
If you're in the US, two days ago was your annual reminder of exactly the answer to that question.
We can definitively punish bigger companies. The issue is the geopolitical positioning, and basically agreeing that we accept smaller companies in our country / society while another country might develop bigger companies, and in theory have more power. Maybe more actual military power.
So unless it's a worldwide agreement, really hard to make this happen.