I would look for better examples than Twitter to base that claim on. The primary lesson to draw there is that you’ll have a harder time running a business if you act like a coked-up frat boy, which is … not a surprise?
The point is that at even the slightest hint that Apple might compromise Twitter's iPhone App or advertising, Musk has to visit and smooth things over. Have you heard that actions speak louder than words?
If Apple didn't have too much power why would this occur?
Because Elon is a nut and likes stirring up drama? For real, who was the first person to tell Elon that twitter was going to be banned? Was it Tim Cook? Or was it catturd?
We don't reliably know that this was anti-competitive, or even what the meeting was about. It could have been related to Apple pulling advertising — since they're reportedly the largest single advertiser that'd get an HQ visit on its own — or simply that communications had broken down due to all of the fired people not being replaced. That's the larger point here: he's making pointless, stupid mistakes and that means that a lot of things are happening which technically could be part of some big conspiracy but might also be Musk shooting himself in the foot again and then blaming anyone but himself.
