Another huge nail was the strikes - business will continue with or without those on the picket line, but it just moved to where there weren't strikes.
I think people incorrectly ignore the strikes. The workers had very little leverage and gave a huge opening for Netflix who had the capital to move production anywhere.
Also, at the time (and still somewhat today), Netflix was the only one to really think globally about a content strategy.
Eh, I think international production was already a thing for quite a while. I remember so many shows shot in Vancouver, for instance, even pre Netflix. But like every industry, remote work has gotten easier and the forcing-function of COVID showed that you can have some writers in Toronto, a crew in the Czech Republic, and post-production in India - you didn't need them all in LA on union contracts and payscales.