I would say that the bigger part in this phenomenon are playing Poles that are working abroad. Those few foreigners don’t make a big difference if you ask me.
The Irish/english real estate companies tend to create a rush/panic situating thereby causing a spiraling price increase, the pole working his guts out in GB is not going to fall for this trick. He will do his home work and avoid those overnight cowboys.
There is still the two price system in Poland, price for the locals and the price for those from overseas.
Like anything else real estate works on price and demand.
Overseas companies still see Poland as a cheap real estate market and they just pay the asking price.
The poles who have worked in other countries have not done there country men a favour.