I doubt that Brohm is telling these kids that their scholarship will get yanked. I'll bet he's telling them that if they want to stay, they're welcome to, but based on X, Y, and Z (scheme, talent, incoming recruits) that there's very little chance they'll ever see the field. And that hey, if you want to transfer, we'll do everything we can to help you in that process.
He doesn't seem like the type to just "run players off". But I'm sure he's telling them with full honesty that if they are in this to see the field, it's probably never going to happen if they stay.