Based on the analysis above, it would seem that sellers are not (in almost all cases) accepting home sale contingencies unless the home that must be sold is already under contract.  Here's the logic....

• A seller would almost never accept a contract with a home sale contingency without a kickout clause to allow them to move on to a different buyer that didn't have a home sale contingency.
   
  
• There are only 5 properties in the MLS that are under contract with kickout clauses.

It would seem that most buyers are likely waiting to make offers until they have their own properties under contract (thus eliminating the need for the kickout clause) AND/OR most sellers are not accepting offers with home sale contingencies unless the buyer's house is already under contract (thus eliminating the need for the kickout clause).

If you are a buyer, I would certainly suggest the strategy outlined above (and the only one that is apparently working with sellers right now) --- get a contract on your house and THEN make an offer on the property you would like to purchase!