"Is there not some way that EBay can make sure that these listings expire and are removed? "
Maybe but will they? Probably not. As with all listings, it up to the potential buyer to read the details before bidding or buying.
As you have seen, some of the sellers are not diligent in removing listing that have expired tickets or maybe they figured no one would buy them once the event has taken place.
As a buyer, you will just have to buy tickets far enough in advance to not have to worry about tickets being expired.
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Non payers should get unpaid item strikes and be added to block bidders lists. Period.