You're right, you can go out and buy HR24s at $199 a pop. I got 2 of them as part of my install, so I paid $100 total after credits. For a difference of $300 you bet your ass people are going to try and work the system with DirecTV to get them through the installation channels. DirecTV created this problem for themselves by structuring their pricing and lack of equipment selection the way they did.
Fwiw, this "System" you speak of, came from DISH Newtork.
It was DISH that went to leasing recvrs first and it seemed to work, so D* adopted it.