Yes. They are. If they weren't, no one would have these problems. But they all do. I know everyone likes to pour over them with a microscope and drool over their flaws because they're Tesla, but many of the issues commonly attributed to them are common with all other OEMs, you just have a bunch of armchair engineers who don't know WTF they're talking about.
They degrade before they fail.
No shit
If tesla wanted to provide a warning of a failing battery that pretty much always worked it could have wired in a load test and went off voltage drop under a heavier load.
Once again, I did this for a living, for a decade. We would constantly have cars with failed batteries, we would bring them in, charge them up, test them, they would pass, we'd send them on their way, and they would fail again, and come back for replacement. Our load tests also tested the alternator.
I worked on BMWs for years and they would regularly come in with the same problem, with no warning, even though they had a similar detection algorithm that mostly worked.