There is truth in what you’re saying, but I think it’s missing a lot of nuance especially when it comes to why a lot of the things you’re saying are true. A few quick things:

instead of going with DOS

Apple developed the original Mac OS to be the first major GUI OS, and MS was left struggling to catch up. Going with DOS would have been a major step back, and set computing back significantly.

always been isolated from the PC ecosystem.

which was originally more to do with IBM than Apple.

You could barely read PC files, and most PCs couldn’t read Mac files without external software until Apple changed to Mac OS X in 2001.

This was less because Apple wanted it to be that way, and more because Microsoft wanted it that way. The reason things switched in 2001 isn’t specifically because of OS X, it’s because Apple did a deal with MS in '99 or so (and MS only did it likely to avoid more regulatory scrutiny after losing an anti-trust case) and part of that deal was more interoperability. Apple had advertising campaigns basically saying “don’t worry, you can switch to Mac and bring your files with you.”

They’re doing nothing different from when they started.

This is also true, but again misses a crucial piece of context - they do it that way because they think it’s generally better and makes better products, and I think you’d generally have to be pretty unstable to argue otherwise. Think about snapshots in time - in the 80’s when it was DOS and original Mac OS. Do our computers look and work like DOS or Mac now? Compare modern laptops to a '94 powerbook or whatever was on the PC market. The modern phone and the modern OS compared to what came before iPhone. Or take a gander what Android looked like pre/post iPhone announcement; spoilers, it was a blackberry knock off instead of an iPhone knock off.) Even Windows today looks and acts more like macOS than it has since probably the 3.1 days.

Even some of the more seemingly shitty decisions follow this pattern. Remember, iMessage came out at a time when messages cost either $5-20 for what would now seem like an absurdly small block of messages a month or $0.10 a message. Its initial value prop was that it was stupid to pay that much and if you bought an iPhone you could cut your bill way down. Or Lightning instead of micro USB. MicroUSB couldn’t fulfill all of the functions Lightning could, and it’s a worse connector for a lot of reasons.

I mean, that said, iMessage was definitely designed to keep you on iPhone and it’s being deliberately used as lock in, and there are plenty of other shitty things about Apple (like any other corp) but the virulence with which people hate it is often just because they do not get it any more than I see people mindlessly bash Linux usually with insults that haven’t been true since 2006.