It is a point of question, whether the seller would gain higher bids in the long run, if eBay prevents sniping from being reliable. On the one hand, if all bids are regular proxy, bidding wars will occur, driving up the bids as the auction proceeds along. On the other hand, if snipes are being placed, higher bidders without sniper service will tend to be complacent that their bids are high enough, as long as they can see no-one beating them. The added amount of snipe wins does increase the bids at the end of course. But I believe the bean counters at eBay have weighed this issue carefully and decided that overall, sniping results in ended auctions with lower average winning bids, for those auctions that have sniped bids, compared to similar items' auctions where no snipe bids are placed.
eBay would rather level the playing field for beginner and unsophisticated bidders, and reduce the advantages that expert bidders have previously enjoyed.