It's easy to underestimate how inferior MS-DOS was, unless you lived through it. Windows (3.x and later 9x) was slightly better, but still had severe issues. Modern Windows is, from what I've heard, a lot better, so the incentive to migrate is not as strong.
> Today, almost all kids use Cell Phones, which are all locked down.
Not just cell phones; with Secure Boot and BitLocker, computers are more locked down too. In particular, BitLocker means that it's harder to share disk space between Windows and an alternative operating system; back in the MS-DOS (and Windows 9x) days, it was not unusual to install Linux in a directory (or a disk image file) on the same partition used by the other operating system.