It is a slippery slope fallacy though. Limited trust busting causes exactly one thing: limited busting of trusts. If you're not a dogmatic anti-statist then you should have no problem admitting we should empower the state where evidence suggests doing so will lead to better outcomes, and you yourself have admitted state intervention would lead to a better outcome in OP's hypothetical.
Oh how the cool rational facade cracks under the pressure of a case you can't wave the holy sacrament of the free market at and declare solved.
Sure, given that states exist I'd prefer that they'd be the least harmful/most optimal as possible, but it doesn't follow that that means I prefer the existence of government. Just as if you support free market policies in one scenario it's a non-sequitur to argue that that means you support them in all.
What many fail to realize is that the institutions that are supposed to be solutions to problems with public goods, externalities, market failures, and other justifications for government, are rife with public good problems themselves.
