How so? Android has a file system that's accessible to the user out of the box, and there are numerous file manager apps on the Play Store in addition to whatever the OEM packaged in the Android OS image. While the Play Store may be a walled garden, Android doesn't stop you from installing APKs from third parties.
In addition to that, Android has had mouse support since at least 2012. It took Apple what, 8 generations to add it into iPad OS?
However, your overall point is correct. the Ipad is more successful as a "productivity" tool than Android among regular people, despite the suite of Microsoft Office apps being fairly similar in quality across both. I'm assuming that Office style apps are what's mostly being used, and not specialist apps like Procreate or Affinity which are iOS only.
My guess is that people are more willing to buy Apple for tablet productivity as their support is more reliably available and it's easy to get third party accessories. On the Android side there is no such guarantee. Samsung is only OEM even attempting to compete with the iPad Pro, but its support doesn't have the same reputation and accessories aren't always available in all markets.
This is why I wonder about the reasoning in the article. You have platforms that are NOT walled gardens, where you CAN write your own great file manager and those also have same ballpark hardware, yet nobody rushed to write this groundbreaking filemanager that would trigger platform success remotely comparable to iPadOS. Maybe, this is not about walled gardens and filemanagers? Maybe there are best tools for certain tasks and for author's job tablet is just not the right one? Since I got my first ipad 10 years ago I almost exclusively read things on it instead of my notebook. And I read a lot and it is part of my work. But I never expected it to replace my notebook or phone.
Android has a file system, but almost every app goes out of its way to hide that fact from you. I have almost no idea where any particular app is going to save files to, and so it's playing needle in a haystack every time I want to open a file created by one app in a different one.
This is another case where Apple didn't invent something, but made the best version of it.
For a device that didn't have a public file system until recently, the iPad's both works and makes sense. It's iPod, mobile phone, Bluetooth headphones all over again, on a feature level.
In addition to that, Android has had mouse support since at least 2012. It took Apple what, 8 generations to add it into iPad OS?
However, your overall point is correct. the Ipad is more successful as a "productivity" tool than Android among regular people, despite the suite of Microsoft Office apps being fairly similar in quality across both. I'm assuming that Office style apps are what's mostly being used, and not specialist apps like Procreate or Affinity which are iOS only.
My guess is that people are more willing to buy Apple for tablet productivity as their support is more reliably available and it's easy to get third party accessories. On the Android side there is no such guarantee. Samsung is only OEM even attempting to compete with the iPad Pro, but its support doesn't have the same reputation and accessories aren't always available in all markets.