Absolutely true. This group of people is known as "the general public". It wouldn't be particularly useful to aim hardware and software at a selection of technical users who make up a fraction of the population.
What does this even mean?
Luckily, you don't have to think about this, no DRM.
Really, this sums up your statement. You've "heard".
You seem to have this idea that a locked down and/or restrictive device is always a bad thing. The mass market appeal is that the user gets a static experience that is consistent across devices and even platforms, that is difficult to break and is secure. Regardless of any opinions, iOS is no less secure than the competition and is certainly more difficult to break.
Also, what are you comparing? It seems you're comparing all Apple platforms against all other major platforms (whether they be desktop or mobile), which doesn't make much sense. OS X is no more restrictive than Windows is, and the Linux userbase is completely different to that of OS X. iOS is more restrictive than Android, absolutely, however this goes back to my UX point. I very much doubt you're comparing OS X to Android.
Different strokes for different folks. If I weren't now a full-time Linux user I'd be back on OS X, and despite the fact I have an iPhone and it's my preference, I'd still be happy with a Nexus 6P. For the technical bunch it's all much of a muchness, and for the average Joe, it's what they're comfortable with more than anything.
All that being said, I hate Windows.