You can get lattice FPGAs for a few dollars each from distributors. Zynq's in volume are reportedly as $15/each. Tools are free.
If cost is the main concern, then how low do you need to go?
An open FPGA arhitecture is a good thing, but it will require something akin to the RISC-V effort to make it happen. (ie major DARPA/NSF, academic, industry backing to bootstrap). Let's see what happens...
I linked to that above. The conversation moved on because, as your paper noted, what they created lacks a lot of the functionality and even core elements of commercial FPGA's. I agree academics can do most or all of it but it will take more than one at Master's level to be competitive.
If cost is the main concern, then how low do you need to go?
An open FPGA arhitecture is a good thing, but it will require something akin to the RISC-V effort to make it happen. (ie major DARPA/NSF, academic, industry backing to bootstrap). Let's see what happens...