AIUI SawStop are in the process of licensing their technology to other
tablesaw manufacturers.

They do seem to do things somewhat differently in the US, with
splitters instead of riving knives - and it does seem very common to
leave the crown guard off there.

In the UK (and I believe the rest of Europe) properly adjusted riving
knives and closely fitted crown guards are mandatory in the workplace
- along with a ban on dado sets and severe restrictions on deep sawing
- makes the chances of a finger/blade interaction very much lower.

It doesn't eliminate risks here - and if could buy sawstop built in or
have it retrofitted at a reasonable price, I'd buy it- but I'd be
interested to know the relative frequency and severity of tablesaw
accidents in the US compared to the UK.