So what changed? Well I think the biggest notable difference between then and now is then bitcoin seemed to be going only up. Now it seems to be going down. When bitcoin continues to steadily go down, it is a significant concern because Tesla will have to take losses on the cars it sells and will have reduced gross margins, which will result in their stock price tanking.
Musk smartly decided he did not want to risk his half a trillion dollar company on random bitcoin fluctuations. It is probably the right decision (although certainly covered up with false reasoning) but he should have never reached this stage. Tesla should have never taken bitcoin without provisions for automatically converting it into one of the currencies it pays its costs in.