I think 30 days is really reasonable to see if something shipped or not. Maybe eBay could do more to alert you but if you purchase something you really should follow up and make sure you're getting it.
But that's separate right? UPS losing it is different than the seller never shipping it. In the former you should have paid for insurance, and the latter you should know within 30 days if it shipped.
They really can't. This opens up the buyer and seller to myriad scams. You'd be surprised at how many buyers contact the seller, having no clue what site they bought the actual product from.
