Mainstream?
Well, yes. Free market economics has become mainstream since Thatcher put the run on the British Socialists.
Certain unreconstructed 'big thinkers', however, continue to sneer at the doings of mere 'shop-keepers'.
This would include neo-Marxists, assorted 'communitarians', and you Rooseveltian types. ;^)
Almost all the ideas now being debated (which were previously off the table) came from the Cato Institute. The second most quoted think tank in the world.
As much as the big government fans hate it, facts are facts. Sorry to disappoint you, but you better get used to it, it's only going to gain more mainstream support as time goes by.
"Nothing is so powerful as an idea who's time has come".