Have you seen the new DAL scope that will be inked in if the JCBA is signed in? Your answers on any further growth are there, basically none. FWIW There is a limit on aircraft numbers and takeoff weights, etc. Check it out.
Lightningspeed is pretty much right. Also The CRJ1000 will be over the max takeoff weight thus wouldnt be allowed to be flown by a regional for DAL.