I don’t think politicians worry about delivering on promises to voters one bit, at least at the congressional level. Just look at the re-election rate statistics. If you are a house member in 2008, your re-election chances are 94%. Only 6 in 100 lose their job every four years. They just make promises and then do whatever their lobbyist benefactors want them to afterwards. They know the public will forget all about those broken promises the next time election day rolls around.
Also, I’ve never heard a single politician run on a platform of keeping home prices high. If anything they run on a platform of “increasing home ownership” which is just code for more government backing of loans.
I am not saying this is good, I’m just saying it’s reality.