Well, the official version is that Robert Moses wouldn't let O'Malley declare eminent domain, seize the land & build a brand new stadium where he would own all the revenue streams. LA officials had come east to look at the Washington Senators, but O'Malley let them know he might be interested ... & the rest is history.
Still, you got to wonder, the make history bringing Jackie Robinson onboard, (had Roy Campanella also joined then, or later?), win their first 'Series ... against the Yankees! And O'Malley still boogies?
Small wonder Brooklynites despise the O'Malley name.