District are absolutely not about sending more teams to CMP. Increasing the size of CMP or moving to the 2CMP is for sending more teams to a CMP.
Districts are about giving all teams the full engineering experience, not just those than can afford $4,000 to attend a second event. In real engineering you iterate, iterate, iterate. In Regionals you build a robot and get one chance to test it in the “real world”, unless you have an extra $4k. In districts you build a robot, test it in the real world, take it home and refine or improve it with the hopes of performing better at your second event. If you do well enough you get a chance to do that again with DCMP. You also get more ability to improve at the individual event since you are guaranteed 12 matches instead of up to 10 or as few at 8 and you have a higher likelihood of making it into the playoffs too.
Comparing the District System to the Regional System is like comparing my 2006 Ford F250 to my 1973 IH 1210. Both will carry 3,000lbs or more of what ever and haul 6 people, 7 in a pinch, have 3 pedals to operate it and will drive all 4 wheels but the similarities end there.