By a Dutch auction, are you referring to a sealed second-bid auction, or are you referring to a second-item auction? Or are you actually referring to a descending price Dutch auction?[1] If you are referring to a sealed second-bid auction, you're right that it would definitely eliminate sniping, but it probably wouldn't be beneficial for eBay, so it's not going to happen.
First, with eBay's current bidding system items are already auctioned for a very full price, and it's better for eBay for prices to be high. Theoretically a sealed-second bid auction would cause people to provide their maximum willingness to pay, but as a matter of uninformed consumer behavior I wouldn't be surprised if prices were actually lower with sealed bids. Second, with the current system people are much more engaged with eBay than they would be with sealed-bids, because eBay gets to send them status updates on their auctions when they get outbid, which can cause them to either go back to the site and increase the bid (and potentially bid on something else while they are there), or bid on an alternative item which decreases the cycle rate for bidders. Third, bidders may actually prefer the current system, because they can know before the auction ends whether they have been knocked out or not and can move on to acquire goods through some other means.
Edit: Actually, it turns out that if everyone on eBay were using sniping, it's essentially the same as a sealed second-bid auction, economically, because of the proxy bidding (or very close, due to the way bid increments work). But time extension is a different issue. Given that prices would be open still, I would expect that the prices end up near the same place that they do with sniping. Potentially the prices would be slightly higher because all of the bids would be open rather than just the bids made before the deadline which could foment more competition, so that criticism doesn't apply.
In any case, from the consumer's perspective if you want to win the auction it doesn't really change your strategy. You should bid the maximum amount you would be willing to pay and make sure its more than anyone else would be willing to pay. With proxy bidding you can always win by paying too much. If you've ever lost because of sniping it's because you didn't set your bid high enough to beat the snipers. (What, you thought you would get a deal on an auction site? No, this is winner's curse territory.[2])
First, with eBay's current bidding system items are already auctioned for a very full price, and it's better for eBay for prices to be high. Theoretically a sealed-second bid auction would cause people to provide their maximum willingness to pay, but as a matter of uninformed consumer behavior I wouldn't be surprised if prices were actually lower with sealed bids. Second, with the current system people are much more engaged with eBay than they would be with sealed-bids, because eBay gets to send them status updates on their auctions when they get outbid, which can cause them to either go back to the site and increase the bid (and potentially bid on something else while they are there), or bid on an alternative item which decreases the cycle rate for bidders. Third, bidders may actually prefer the current system, because they can know before the auction ends whether they have been knocked out or not and can move on to acquire goods through some other means.
1: https://en.wikipedia.org/wiki/Dutch_auction
Edit: Actually, it turns out that if everyone on eBay were using sniping, it's essentially the same as a sealed second-bid auction, economically, because of the proxy bidding (or very close, due to the way bid increments work). But time extension is a different issue. Given that prices would be open still, I would expect that the prices end up near the same place that they do with sniping. Potentially the prices would be slightly higher because all of the bids would be open rather than just the bids made before the deadline which could foment more competition, so that criticism doesn't apply.
In any case, from the consumer's perspective if you want to win the auction it doesn't really change your strategy. You should bid the maximum amount you would be willing to pay and make sure its more than anyone else would be willing to pay. With proxy bidding you can always win by paying too much. If you've ever lost because of sniping it's because you didn't set your bid high enough to beat the snipers. (What, you thought you would get a deal on an auction site? No, this is winner's curse territory.[2])
2: https://en.wikipedia.org/wiki/Winner%27s_curse