I would expect loyalty, if any, would develop more with editors than publishers, which are, despite what the Supreme Courts says, not people.

For my non-fiction computer books, I sort of followed around one of my acquisition editors when he jumped around. Well, more accurately, my agent followed him around, but he'd send me an email alerting me of a move and asking me if my next proposal should go his way first. But I happily said yes each time.