FPGAs are also stuck in a lot of niches. Economically, any high volume application where they could useful also means that putting an investment into more cust

FPGAs are also stuck in a lot of niches. Economically, any high volume application where they could useful also means that putting an investment into more custom silicon is then feasible to get a better price margins - ASICs, DSPs, or I recently learned a bit about metal-gate arrays which seem to be mid-way between FPGAs and hard silicon designs. They're stuck in a power niche because they're comparatively high power vs many embedded ICs, and if you're using a lot of power, as you said more desktop chips are economic to apply.