It is Pope who put the idea of EU at first.
EU may seems be ruling by seculars, but when look at the roots, it is still an Christian league.
So they always deny Turkey's desire to join into. They also do not want to lose their median, political and economic profits on it.
The most important reason is, they can not let Turkey develop on it's own.
Now let us look from Turkey's side. Most of the folk supports Erdogan. They are tired and bored of being something what they really are not. They are not pious as Ottomans, but they always shares the same ideology.