Is there an easier way to remove glued-down hardwood than hammer & pry bar?
It is a shame because it sounds as if your parquet is a good sound floor. If it is that hard to remove then you could lay straight onto it but I imagine there are height issues. 

You can hire a small SDS masonry chisel which should get them up faster. Wear ear and eye protection.  I have a larger machine of this type on wheels that I use on commercial buildings. It saves hours of work.