While I do have some alternatives on my Linux system (Obsidian, Espanso, uLauncher, a bunch of scripts), they're not as integrated and somewhat of a pain to maintain properly.
Plus first-party apps like Safari with its fluid trackpad gestures, Photos with its iCloud integration, and of course Xcode, because being able to build/debug things for macOS/iOS is a bonus feature I can offer as a developer.
The list is a lot shorter than 10 or 15 years ago. Most new apps that come out are Electron, but even then there's sometimes no Linux port (Trello, WhatsApp).
I also like the integration between my phone and my computer. For example, taking a picture on my phone and having it show up in Photos automatically, the ability to copy and paste between my phone and computer, the ability to make phone calls on my computer, the ability to share browser windows between my phone and computer, and the ability to use my iPad as a second monitor.
I've been using Linux since Slackware's first release, and still use it today, but it isn't my main desktop for these reasons.
that rules out any Adobe product :)
the appeal back then (and from I hear people say until today) was always how everything is neatly integrated. a coherent system from the hardware all the way up the stack. not sure if that is overselling it but at least that's how I understand is what people are happy to pay for.