More than a decade. I bought my Tesla in 2014, and I recall the announcement because it came after I had bought but before I took possession of my car, and thus I was ineligible for the upgrade.
In hindsight, thank fuck. I would have dropped thousands on it in a heartbeat and never, ever seen it. (Also, that car was a nightmare to own and the service centers were really scammy. Getting rid of it was the best move I could have made.)
