Is SawStop a counterexample to my belief that patents are never (or almost never) useful to society?

Based on the wikipedia page, appears to be without doubt that the patent has reduced adoption in the industry. Perhaps the first company would never have gotten off the ground (to demonstrate effectiveness) without the patent.

Again, though, the advantage of the patent was only realized when the company began selling the saws themselves; licensing deals fell through. At that point, perhaps there may as well have been no patent at all?

Another counterexample. The e-ink patents appear to have been very lucrative, perhaps $100 million. Notably, developed by two undergraduates.

Akasaki’s patents were produced from these inventions, and the patents have been rewarded as royalties. Nagoya University Akasaki Institute[22] opened on October 20, 2006. The cost of construction of the institute was covered with the patent royalty income to the university, which was also used for a wide range of activities in Nagoya University.

The first copper-bearing IUD, the TCu200, was produced in 1969. However, problems with patents prevented the device from becoming the first copper-bearing IUD to reach the market. Instead, a poor alternative model (Cu-7 200, Gravigard®) was marketed by G.D. Searle and Company.

“Pioneers of the interuterine device.pdf”