Someone needs to slap you. The 200,700,900 or a common type and the 700 and 900 share many common parts. So if an airline already operates 200 and 700 it could easily start 900 operations quickly. Just like Skywest did.

Oh and rest assurred someone else will operate 900's along with Skywest. That way they can make sure that they can have a pricing competition to keep wages down.