If you've got the land area and the sunshine, solar PVs are cheaper than wind, it's that simple.

Wind is a better fit for Europe where there are far fewer sunshine hours but fairly constant wind due to macro-scale atmospheric weather patterns.

With that said, the cost of PVs is dropping so fast - faster than wind power - that I expect solar to become more important in Europe as well. Even in northern latitudes, solar farms are popping up on land that was previously used for agriculture, and I expect this trend will accelerate. If you're a landowner, you can potentially make more money using the land to generate electricity with PVs than with agriculture.