"Many of the items I've bid on already have a slew of auto bidders and I can't seem to outdo them, even when the price goes several hundred dollars up. Is there a way to get around these, and why is automatic bidding so common now?"
Because you are not really experienced using ebay, you may be misreading the bid history pages. The clue to figuring out who is an automatic bidder vs. those who bid one increment at a time over and over (nibble bidders) is to look at the time stamps of the bids. The time stamp for an automatic bid will be the same, unless their maximum bid amount was reached and they bid again.
You may find that some who nibble, actually do by placing automatic bids but only for a few increments at a time.
The thing is that you biding early against automatic bids, is actually driving up the price, which is why most experienced bidders prefer to place bids as late in the auction as they can or are willing to which is called Sniping. By doing that they do not give others who nibble bid, a chance to bid up the item and not much time at all to react to their bid. However, for a highly collectible item you may get several snipers who will run the price way up. Then it boils down to the person who is willing to bid the most for the item winning, but that bid could be an earlier automatic bid.
"I'm not sure if it's just me, but I think automatic bidding kind of defeats the purpose of bidding-you're notreally there".
Anyone who places a bid within the time allowed IS REALLY There. Often snipers have been watching the bidding for several days.
If you think of bidding on ebay as being a sealed bid auction, like you see at a charity events, where you write out your bid amount, place the bid in a box. Just because a person who arrives late places a bid doesn't exclude them from bidding. Then there are those who even at live auctions wait until the bidding slows down who will jump in and bid, like some do on Storage Wars.
The one practice you want to avoid, is placing a bid for much more than you are willing to pay for an item called, Nuclear Bidding. If another bidder does the same thing, one of you will end up winning and being faced with either paying what they won the auction for, or not paying and getting an Unpaid item strike on their account.
"THERE IS NO SUCH THING AS FOOLPROOF, BECAUSE FOOLS ARE SO DARNED INGENIOUS!" (unknown)