There are going to be a TON of 50 seaters parked over the next 5-10 years. Yeah mainline is ordering a lot of large RJs but I really bet it will still be a wash or possibly less Regional Aircraft flying around.

Expressjet has what 500 50 seaters, What about Skywest?
PSA? Republic? Air Wisky? Lots of news of large RJ orders but don't forget all these 50 seaters that are on their way out....