Why don’t the bottom of D1 teams play the top of D2 teams to fight for D1?

I'm a bit confused on one part of the DPC format —

Right now the bottom two teams of Division 1 (D1-7, D1-8) will get relegated to Division 2, while the upper two teams of Division 2 (D2-1, D2-2) get promoted to Division 1.

Isn't it more "correct" for the teams to play each other to fight for the two Division 1 slots? The issue with the current system is that even if D1-7/D1-8 are better than D2-1/D2-2, they have to play in a lower division.

i.e. I would think a better way to do this would be to hold a small double elimination bracket at the end of the season where D1-7 plays vs. D2-2 and D1-8 plays vs. D2-1 and then the top two teams advance to Division 1. This forces the top two Division 2 teams to "prove" they can make it into Division 1. Otherwise we can get seasons where the two bottom teams basically just keep rotating because even the original bottom Division 1 teams are better than the top Division 2 teams.

Any ideas on why the format is the way it is? Is it just to get the winners of Division 2 some exposure/experience in Division 1?