There is definitely a lot of that. But that is not the only reason. The excessive housing pricing have gone on long enough now that many people will be trapped and ruined if housing prices stagnate or fall.
People have had to spend far more than is prudent to get a house that is not that great just because there are no other options.
If you are putting all of your extra money into your mortgage payment, you are going to have to rely on being able to sell that home anf move away when you retire. If you cannot at least sell it for the equity you have in it, you will be trapped in an expensive city with no money to retire on and no way to sell and get out.
So I understand why so many are fighting to keep prices high. Their financial future depends on it and I don't think it's greedy to try to avoid financial ruin.