He only lost to Huck because he dropped out earlier for the sake of party unity. The primary was over but Huck hung in for a few southern votes.
As a factual matter, you're right. But, this wasn't like Reagan/Ford in '76, where it was actually a race with an exciting convention. Romney got SHELLACKED, I mean he was obliterated. He spent - I think - somewhere around $40 million of his own money and garnered only 270(ish) electoral votes. That works out to around $145K a DELEGATE. That kind of math didn't work last time, and it won't work this time.
Plus he had wasted about 50 million dollars of his own money on the doomed effort and another 100 million dollars of others, Romney did not want to keep pouring millions of his own money into the losing race.
Romney is always about himself, nothing else.