Because it didn’t make financial sense for them to buy it. The last I read up on the matter it seemed like Musk has lost quite a bit of money on it since he took over. Literally the ONLY reason Musk bought it was because he got into a pissing contest with the previous owners after he claimed he could run it better. He actually tried to back out of the deal a number of times but there was some kind of legal reason he was obligated to buy it after he made an offer