There are many such markets -- real estate, construction, financial services (banking, mortgages, credit cards, etc), agriculture, retail (no, walmart is not a

There are many such markets -- real estate, construction, financial services (banking, mortgages, credit cards, etc), agriculture, retail (no, walmart is not a monopoly), oil, automotive, air travel, I can name many more. The only big national industries that are dominated by monopolies I would say are telecommunications, utilities, silicon, pharmaceuticals, rail, and even most of these have a few more companies than two. Granted, 3 telecoms is not much of an improvement over 2, but nevertheless your claim is broadly speaking false. Are there private equity firms trying to consolidate? Sure, but in any of the above they haven't really met with much success.