The US stopped doing it around 2014. They also stopped doing it in JFK before they stopped doing it in LAX; so when I flew in one side of the country and out the other I had to argue with the clerk....

Edit: I see wikipedia mentions the move to electronic record keeping instead of adding it to your passport: https://en.wikipedia.org/wiki/Form_I-94#Automation_at_sea_an...

Are you a U.S. permanent resident or U.S. citizen?

It only works for foreigners, I believe, as U.S. residents don't need I-94 forms (the old cardboard slips). I'm also not sure if it works for Canadians, as Canadians can also travel to the U.S. more easily.