Again, there's only about 15,000 regional pilots who'd all love the chance to fly for United...
Divide that by three, you still have 5000 applicants, and it'd take UAL close to a decade to retire that many people. This doesn't even consider up-and-coming students/CFI's or the many guys at LCC's/majors.
Point being, a program like this doesn't seem close to necessary yet. I hope it just means they're worried about their own pilot supply down the line and hire accordingly, but if and when CFI's start getting hired before guys with thousands of hours in a jet that says United Express on the side, well, that wouldn't be cool.