And it seems like all of the “similar” cases where companies are sued for antitrust that are often cited on HN are when two or more companies collide with each other.
There is a reason why HN lawyers get all hand wavy when asked to come up with similar examples.
In similar cases, they absolutely have talking about what is illegal, regarding anti-competitive behavior.
I would encourage you to read up on similar cases, in order to see what courts have said on the matter.
And the courts have said that it does not require a literal, singular monopoly in order for anti-competitive behavior to be illegal.
All that has to happen is for a company to have significant market share, for anti-competitive behavior to be illegal.