This is exactly why scope is the #1 section in any Legacies contract. If they could have gotten away with that, they would have about 15 years ago!

Not going to happen and to stay at an LCC in hopes of being absorbed by a Legacy in the future would be a big mistake IMHO.

Stay at a LCC because your home every night, they base you in a city you want to live, you don't want to be bothered learning different aircraft types throughout your career, or you don't want to have to think about how to best invest your excess 401K contributions.

But don't stay there thinking that one day a legacy will purchase you.

I could maybe see a day where the LCC's combine, or even SWA buys one for more airport access and to put down some competition, but really can't see a legacy wanting it (or it's employees to allow it in the manner you suggest).