> Real, actual capitalism results in competition which drives prices down, as long as there are two or more competitors and antitrust law is enforced.

I generally agree with you here, (though it's a bit simplistic for things not directly related to price: for example good luck avoiding arbitration clauses)

> Which is generally the case.

Now our opinions differ. Lina Khan was an exception, and I certainly can't imagine the current regime standing up against money.

Some recent(ish) ones I think have been less than great for competition

  HBO / Discovery? 
  Facebook/Instagram/Whatsapp? 
  LiveNation / Ticketmaster? 
  Disney / Fox? 
  Charter / Time Warner Cable? 
  AT&T / Time Warner? 
  CBS / Viacom? 
  Comcast / NBC? 
  JP Morgan / Chase? 
  CVS / Aetna? 
  Cigna / Express Scripts?
  Sinclair Media