Elon Musk is really an imbecile, an idiot disguised in the persona of faux-brilliance.
This is not about cutting off an API.
This is about destroying any remaining shred of trust with the developer community. With trust gone, there is only a burning pile of, well, no developers.
He wanted to build an 'everything app.' The idea now is just LOL. What developer would dare to commit any time and effort to someone who has destroyed TRUST.
TRUST is everything. When its gone, it doesn't come back.