Will it really kill lead gen though?
If anything it should put more emphasis on pay per sale instead, and perhaps this is something that should be suggested to the advertisers.
I've always found it amazingly frustrating that you can get a lead payout that's in excess of $50, but if you're doing a sale you're lucky to see $20... which is fucking moronic, because the sale is likely to turn out better for the advertiser than the lead.