I think these days FPGAs have just gotten cheap enough that the economics of making custom chips doesn't make much sense for the volumes these kinds of products tend to sell.
Plus FPGAs add a lot of flexibility (e.g. multiple systems, enhancements), and they're really not that expensive. Especially in relatively low volumes compared to an ASIC.
> FPGAs are pretty expensive I imagine compared to some 40 year old cpu design and 1kb of ram.
The MiSTER Pi set me back $180 and is perhaps my favorite purchase of 2024. It'll run almost any system made before the year 2000 and the gap is rapidly closing for lesser-appreciated consoles like the Saturn and Jaguar. This represents a tremendous value; it's hard to argue with that kind of money for an entire century of gaming. I heartily recommend picking one up.
https://en.wikipedia.org/wiki/Term_of_patent
The SNES came out in 1990:
https://en.wikipedia.org/wiki/Super_Nintendo_Entertainment_S...
Every patent on the original SNES should have expired by 2010.