> At the end of the day, it's really not hard to prevent table saw injuries. Use a riving knife, don't twist the wood and you'll pretty much never get a kickback.
isn't this just another way of saying "don't make mistakes"?
If you're about to remove the riving knife, or making a cut that may twist the wood you should immediately ask yourself if there's a more appropriate tool to use or way to make the cut. If you continue anyways I'd see that as negligence as opposed to a mistake. (To expand on twisting the wood, the longest side of the piece should always be held against something while cutting. So on a rip cut it should be held against the fence. And on a cross or angled cut it should be held against either a crosscutting sled or miter gauge)
Not saying mistakes don't happen. I'm sure there are instances of people doing everything right and still getting injured. But as I explained I don't think it happens often enough and the injuries aren't serious enough to make the risk so unacceptable that we need to add $500 to the price of every new tablesaw.
Wood often has hidden stresses within its structure. An apparently straight length of wood can cup/bow/curl quite markedly when cut. So you can't always know if a particular rip cut will result in the wood binding between the fence and blade leading to kick back.
On the price difference point, I have a portable Dewalt table saw that cost about AUD$1100 with a stand. Saw Stop didn't have a portable version when I purchased. Now that they do have a portable version, it is about AUD$2000, roughly twice the price of similar models from other manufacturers (at least here in Australia). That's quite a price difference for hobbyists and home gamers who aren't deriving an income from the tool.
It's a little more complicated than that. Even with a riving knife, you can still get kickback if your blade isn't aligned properly -- and most cheaper saws need a tune-up before being used.
Not saying mistakes don't happen. I'm sure there are instances of people doing everything right and still getting injured. But as I explained I don't think it happens often enough and the injuries aren't serious enough to make the risk so unacceptable that we need to add $500 to the price of every new tablesaw.