Your assertion seems to imply that there will be a point of no return where users are no longer able to stop buying apple hardware to run the software they want, and that therefore people should do so now.

If that's not what you're saying then your point is effectively moot, because if indeed Apple's platform control gets too egregious for some individuals then those people will switch at that point so there's no point in panic-switching now just in case.

In other words, users will switch when what Apple is offering does not meet what those users require. Some users will literally never care because all the software they use is signed and gatekept and so on; some users have jumped ship already because they want to be able to change whatever they want whenever they want. If things continue to "slippery slope" then more people will hit their own tipping point but asserting that it's going to happen all at once and apply to everyone is nonsense.