How is this so hard for you to understand, iMessage gets shoved in people's faces and is activated automatically. It's extremely anticompetitive and isolates people not on apples platform. It's far worse than anything microsoft did in the 90s.
How exactly is anyone ‘isolated’? There just doesn’t seem to be any basis for saying that that.
All it does is improve the use experience for people who do use Apple’s platform. They are just as able to communicate with people who have SMS as they were before and vice versa. You are going to need to explain this ‘isolation’.
Literally billions of people use competing messaging apps such as WhatsApp or Facebook messenger.
It's not just preinstalled, it forces you to make an account to use the phone and inserts itself into what was previously the most popular messaging system in the US. If apple did something like this with the mail app everyone would probably completely flip out, the only reason they don't is because SMS was already terrible.
The fourth hasn’t been true for a long time.