Markets can remain irrational, or colluding, far longer than you can stay solvent (or even alive).

For example, while the Phoebus cartel only really lasted from 1925 through to 1939, 1000hr incandescent light bulbs remain the standard offering till present day. Profitable market manipulations are sticky.

The whole notion that markets are efficient is just a mathematical construct that has become very dogmatic for people. But if you look into the details, markets are efficient under the assumptions of perfect information and infinite time. Neither of those conditions are present in the real world: we neither have perfect information nor infinite time.