But reading your post and this one:
> ... and then it's got to connect to the cables off to the system - all 100 to 200 wires down a cable that's a couple meters long, and thin/light enough for someone to use 8 hours a day without getting repetitive strain injuries. Do you know how thin that makes each wire? Try calling a few cable vendors and ask for a small diameter cable with 200+ connectors that will actually conduct a signal without significant crosstalk and let's see where you end up on price.
It also mentions the system being mounted on a cart. This seems like an area where technology can make some serious improvements. Mount your ADC (for which speed, accuracy, power requirements, and channel counts have been steadily improving) within the probe, and stick a high-speed serialization/deserialization chip on the other end of it, and run power and digital data over a much smaller, cheaper cable. That's the direction that industrial I/O is going, at least.
I guess the point of all this is that there are opportunities to make significant changes to the way these devices operate that will make them easier to build. Switch out the ASICs for GPUs, the analog cable for digital, the custom computer for commodity hardware, and so on because these technologies are more capable than they were in the past.
Believe it or not, there is no plot for using outdated technology and keeping the prices high. This is a quite competitive market, and engineers working in the field are not stupid. There are already some machines using GPUs for the signal processing. I think there might also be some machines with ADC in the probe, although this is not simple (you also have to put the transmit side, and the rx side has to be of good quality) and you can really benefit from extremely high acquisition rates, so depending on what you want to do such a digital link is not trivial + plus you basically duplicate a large part of the machine in each probe if you do that, so I'm not even sure this will be better in every cases...
Also; a new machine can take several years to design and bring on the market.