Facing obsolescence problem in FPGA based PCBs. Is it wise to mount FPGA on piggy backed board instead of assembling the FPGA directly on PCB?

Thanks for the response. Do you mean irrespective of speed such connectivity not an issue? I studied some literature where they are advising to be very carefull in FPGA board design about impact of discontinuities arises out of such connectivities mostly on reflection and jitter. Is any specific test to be done to qualify such deisgn on socket or piggybacked connectivity?