An industry ripe for disruption. My guess is that patents and military contracts are propping up the few entrenched vendors.
Eventually, the simple FPGA designs from 20 years ago will perform "good enough" when shrunk down to modern manufacturing processes. Only then will the new age of reconfigurable computing begin.
As far as I've seen, the main users of FPGAs are developers eventually targeting ASICs.
A video codec or whatever might first be implemented in C++, then 'translated' to verilog and tested thoroughly on an FPGA. Having solved all the logical issues, and detected a lot of potential timing issues, the HDL design could be translated into an ASIC design, and heavily simulated. Then, confident that the design is good, the company could spend the bucks to make a mask for mass manufacture.
You do occasionally see people using FPGAs where they need the zero latency of a hardware design, but only need a couple of devices. Usually this is in RF research labs and the like.
I suspect most people with compute problems would be better off using a GPU.
Eventually, the simple FPGA designs from 20 years ago will perform "good enough" when shrunk down to modern manufacturing processes. Only then will the new age of reconfigurable computing begin.