Retail vs wholsale short sale transactions

I have been involved in short sales since 2006 before most in the Tidewater area of VA even knew what they were. I began with an investor, buying at a reduced price, then closing back to back with the end buyer within the same day or within 24 hours. This was done with little efffort. Eventually, as the market changed and changed again, these became more difficult, but are becoming easier with lender streamlining and education. Over the past 4 years, I have worked with many investors, some ethical, and some not so ethical, looking at distressed sellers as their meal ticket with little to no empathy. I would love some imput, particularly on the subject of A-B-C transactions.