The final hurdle: Can the buyer qualify for a loan?

The California Residential Purchase Agreement gives the buyers in most cases 21 days to remove all of their contingencies.
The contingency most contracts leave to the last is the loan approval, which makes a lot of sense.
Why would buyers put their deposit at risk, which is what you are doing when you remove your final contingency in writing, before they actually know whether or not they can get a loan large enough to buy the house of their dreams?
This puts the pressure on the buyers and their