When pricing tools you have to consider the cost per time-unit, or cost per use. Looking at the total cost is a waste of time.

How often do you input text into a computer (or sleep in a bed, or whatever).

What is the hourly (or daily) cost of it over some reasonable timeframe (1 year, for example).

At what price point is owning a better tool worth it? (health wise, opportunity cost wise, etc).

Yes, but your time-unit won't change if you get a Kinesis Advantage over a regular keyboard, so, even per time-unit, it's still more expensive.

I suppose that's true in a tacky arithmetic way. Shit keyboards are basically free. They also ruin your hands. So you have to prioritize a little. Having used the same Kinesis for six years I don't have a lot of sympathy for not being willing to shell out <$50/year for the most important part of the computer. In a discussion about someone trying to sell me a $150 dollar version of the free shit keyboard it seems even more disingenuous.

Yes, but people are reporting that the very expensive keyboards are not helping them. So, we are not solving a problem for $300 or whatever, we are taking a chance at solving a problem at $300. That's a different optimization problem, with a perhaps different solution.

If there is pain involved with one option, then it's logical to assume that time will change. When I do get wrist pain, it does cut into how I use my time.

Sure, but that would be assuming you personally are experiencing this pain. It goes back to what someone else in the thread said: Don't go looking for solutions if it isn't a problem you're experiencing.