I often find people first assume something that isn't in US anti-trust law - that one must have a "monopoly" in order to be problematic - and then use a narrow

I often find people first assume something that isn't in US anti-trust law - that one must have a "monopoly" in order to be problematic - and then use a narrow definition of monopoly to conclude that no legal problem exists. US law talks a lot about "market power", not monopoly. And... > economy dominated by big tech we both seem to think it is clear that there is market power.