This is a question that I have wondered about for a while now as I find I use ebay less and less for both adding to and selling parts of my toy collection. I started using ebay more than 10 years ago when you could only have a US based account and everything was listed in $. At this time the Internet was still young and ebay was a place for ordinary people to buy and sell stuff. The fees were low and there were very few categories, but you could search around and find many great items for good prices. Even selling stuff was fun back then as with low fees it didn't matter if your items only sold for a small amount.
I would often buy items from people in the US and because there was no paypal or easy way to send money I would stick actual dollar bills in the post. The sellers were happy to wait the few days it took for the money to arrive, and they got cold hard cash with no fees taken.
Over the years with the introduction of paypal and more currency options ebay did get better, and more fun to use. But then people started getting greedy. Ebay kept upping the fees, paypal also. Then on certain categories you began to be forced to offer free shipping. Also sellers started to get more greedy, and maybe a bit more knowledgeable. So the prices of the items went up, and also the price of shipping as sellers realised that you needed to over charge for postage to try and claw back some of the money you lost of fees.
Nowadays I have pretty much given up selling small items on ebay. If I list a single star wars figure for 99p, ok there are no listing fees, but you still seem to end up making nothing. It seems unless you are selling something that is worth more than ten quid, just don't bother. Even then by the time you have paid ebays fees and paypals fees you make very little money.
And even my buying has started to run its course. I still look at ebay most days, but I jus look. Most items for collectors are overpriced, with over the top shipping charges. The sellers have to charge these high prices to be able to make a profit, but it just means I don't end up bidding. If you take a look in the action figures/star wars section you can see that more than 50% of the auctions end without a single bid. Again, great for ebay as they still get their listing fees, but bad for the seller as they get charged no matter what. Ebay has now become a market place for people to sell new items exactly the same as amazons marketplace or play.com's market area.
Ebay has moved itself from a place were ordinary people could buy and sell their own stuff, to a place that is mainly aimed at larger firms. They really have priced out the little people.
The real shame is that there is no alternative, it's ebay or nothing. Which is great for ebay, but sad for the collector. And I can't see anything changing anytime soon. Ebay have such a monopoly that it pretty much impossible for anyone to make a dent. There are a few online auction sites but very few people use them, and because people have the ebay greed built in the items that are listed are done so at stupidly high prices.
The only place left for us collectors is fan run forums. I quite like forums, but they are not the same as being able to browse a large market place.
So, has ebay had it's heyday for collectors. In my eyes the answer has to be yes! These days I would rather go to a flea market, toy fair, or trade in shop. Some of my best recent finds have been at trade in shops. And I have even sold some of my excess collection to one as after the hassle of listing the item on ebay, the large fees, the posting hassles, I ended up with pretty much the same amount of money I would have made selling them on ebay.
Does this stop me looking on ebay, no. But it's no longer my first choice when searching for new items. It's probably not even second.