I think one of the major sources of eBay's troubles is their decision to slowly abandon their P2P focus, in favor of the "shopping mall of the internet" model that Amazon uses. Rather than pursuing this model and doing it better than the competition, they chose to ape them, and badly. Like CrazyCatDog said, eBay is the textbook example of what happens when a tech company is run by consultants who don't understand the…
A contrarian view: there is some room to attack Amazon, primarily in the UX department. I wouldn't rule that out as a strategy for growth, but is eBay the right company to execute it? That's where it gets murky. They have a lot of the same usability flaws.
Good luck with that. I've spent over $50K at Amazon over the last decade according to the data I dumped out of my orders. I'm a prime member. Amazon's site isn't perfect, but between the reviews, 2-day free shipping, 1 day at ~$5 extra, and product selection rivaled only by Walmart, I wouldn't look at Ebay unless it was something exotic (5 ton military truck for example).
"Bid" on something? No. Use Ebay's UX compared to Amazon's? Again, no thank you. Wait 5-7 days (at least) for something? Good luck Ebay!