Protected markets are great things, while they last. But when they end, the protected companies pay a huge price. Do you remember when the US car industry lost its near-monopoly position with the entry of Honda and Toyota, who demonstrated that high quality was affordable? When a consumer discovers there is something better after having had no choice, he feels ripped off by the monopoly-like provider. And that ah-ha is disastrous for companies when markets open as customer loyalty is essential to retaining market share. No wonder US consumers waited a decade to recognize that US car quality has improved dramatically. The company that’s going to pay a heavy price for a monopoly-no-longer position is AT&T, the exclusive Apple IPhone network since the to-die-for phone’s introduction. With Apple likely to add other providers in 2011, one would think that AT&T would be working…