Elon Musk has criticized Apple for years. Apple has mostly ignored him

$Tesla (TSLA.US)$ and SpaceX CEO Elon Musk, who is also the new owner and CEO of $Twitter (Delisted) (TWTR.US)$, bashed $Apple (AAPL.US)$ this week after claiming the company has threatened to remove the Twitter app from its App Store, accusing the company of hating “free speech.”
The Twitter app is still available for iOS devices, and there’s no sign that the popular social media app is at real risk of getting booted by Apple.
Tesla and Apple are neighbors in the San Francisco Bay Area, which means that they have competed for talent for more than a decade. Now that competition has extended into Texas.
Both companies need mechanical engineers, industrial designers, materials science and battery experts, and skilled software engineers.
Apple has also invested heavily in developing its own electric autonomous vehicle technology. If the so-called "Apple Car" ever came to market, Tesla and Apple would be direct competitors.
In that context, early examples of Musk tweaking Apple could be seen as friendly rivalry.
When Tesla was still an underdog and upstart, Musk used to call Apple the "Tesla graveyard," according to multiple former Tesla employees who spoke with CNBC. Internally, he would encourage unhappy Tesla workers to go apply for a cushy job at Apple.