Musk promising FSD by the end of the year - year after year - is one major thing that tarnished the Tesla image in my mind. I now assume that he has to believe that in order to avoid lawsuits. Maybe the same is with the computing infrastructure. They need to build it to show that they honestly believed it could work - even though they failed to deliver on their promises many times.
That said, they do make progress and the real reason why it's slow is probably because the problem is actually really hard and nobody has found the fast way to the solution yet.
That said, they do make progress and the real reason why it's slow is probably because the problem is actually really hard and nobody has found the fast way to the solution yet.