The vast majority of the 4 million refugees in Turkey are Syrians.
Question is does Turkey provide food and shelter to all those people? Not at all, only to a small fraction maybe around 200K. And even for that she gets money from the EU. It would be too much to expect anything better from a messy state like Turkey.
The rest are wandering here and there, exploited for cheap labour, women exploited for sex, some getting raped, etc. These refugees don't really cost anything to Turkey! Quite the opposite they became a profitable industry. The most profitable part been their packing on boats and sending to the Greek islands, or to Cyprus. In Cyprus we receive refugees both from the occupied and from the sea at a rate that exceeds our own birth rate. Government officials are crying all day to the EU that we can't let this continue. Notice those refugees pay the traffickers 2-3K US$ per head. I wonder where they find the money... Erdo has nothing to lose from the refugees either. The more islamists in Turkey the better.
We all know that Turkey also attempted to send a number of them en masse through the Greek-Turkish land borders in an attempt to blackmail the EU...
That said, I don't see how the refugee issue has anything to do with Turkey's economic demise. Anyone care to explain?