What are you on about? S106 affordable housing contributions were always figured into the viabilty appraisal so their impact was to depress land values. Thats how residual valuation works. The only people being "bled dry" were therefore landowners. S106 also allowed private developers to get up-front cash payments from RSL thereby easing their cash flow and reducing their borrowings. For a properly run House Builder they had no negative impact on profitabilty.
Mind you not all house Builders were well run, many loaded up with over valued land near the peak of the housing bubble and duly went bust. The same thing happened in the early 90's. Sadly house building has more than its fair share of people who are , not to put too fine a point on it, thick. THe City hates house bulders, their share prices, save for Berkley Homes plc, have always been poor, They have always had the lowest P/E rations in the stock market, and always will because investors don't trust them not to splurge money buying at the top of the market. They have been the authors of their own misfortunes and deserve no sympathy, certainly not over S 106.
Here endeth the morning Rant