Well, Turkey's population is smaller than Germany's, and less than half its GDP. Furthermore, you can be sure the ratios in the European Parliament would be skewed to keep them down.
Greece and Cyprus are a more real problem. Greece has shown that it's not averse to blocking other countries accession (Cyprus was only let in because Greece took the whole Eastern expansion hostage, and now they're annoying Macedonia. Fuck Greece.), and Cyprus show no will to compromise, as shown by their rejection of the 2004 UN Peace Plan.
And then, there is good old Islamophobia. A few years back, when the talks were going strong, the French FN ran adds warning about Muslims invasions, and other far-right party did as well. More mainstream politicians jumped on the bandwagon, including Merkel, who'd prefer giving the Turk as "favored partnership" instead of making them members.
Now, you can't expect a country like Turkey to stay at the West's doors, doing our bidding while being kept in some sort of half-assed "special relationship". Either you accept them as peers, or they'll have to make their own alliances. Now, for years they were at the West doors, so once that one closed, well, it started paying attention to its other neighbors. Turns out they're Eastward of Turkey.
Now, I don't think all is lost. As Leantra showed, the Turks prefers to think of themselves as Europeans than Middle-Easterner (who could blame them for that?). If the EU get its fingers out of its collective arse and get serious about Turkey membership, I think it could still be done, with great benefits for both sides. And if we have to kick out Greece and Cyprus to make room, so be it.
Did I tell you how much I hated Greece's European policy?