If apple buys the modem division, they'll be integrating the modem into the SoC. It will be an advanced process node and they won't be scared of using more silicon area to get more performance. By being on the same SoC, they might combine the application and baseband CPU's into one too using something like trustzone.

Cheapo android handset makers wouldn't be able to afford the resulting silicon - it'll be too expensive due to the large area. It'll also likely diverge from the way everyone else builds modems - no more AT commands!