He said that chrome and Firefox had everything except for tail call optimisation earlier.
Ha! I read your comment as: Chrome had tail calls first, but they were all but guaranteed. I was confused, but once I parsed your sentence that way there was no going back.
I am now in agreement with everything you said. Thanks for clarifying.
FWIW, I don’t think this is accurate (not that it really matters much anymore). All the browsers were in the 90+% support around the same time.