Linux is incredibly productive for me and I'm pretty worthless on other operating systems. And I'm old enough that I'm no longer willing to put in the time to learn a new one.
Ubuntu does what I want; I don't have to configure things and It Just Works 99% of the time. Plus it's free, so there's no financial incentive to use something else.
Say you are a Java (it's easy, common, and cross platform) developer this means you need your Eclipse/Netbeans IDE, a JVM and or some Java based web server. So you have your IDE+JVM on the OS, and development/deployment & test environment on a virtual machine, does it really matter to you if you are running Linux, Windows or OSX in this case? All you use and see is Eclipse, a text editor, Virtual Box and a web browser.
IME, the learning curve for Linux (post-installation, at least) is waaaay less steep than Windows. When I went off to college and got tired of my Dad calling me every few days with another question or concern about his Windows computer, I switched him to Linux Mint and haven't been bugged since. It's too much to expect of the average user to use a Windows computer: constant fears of malware, a system tray polluted with two dozen startup programs that they didn't consent to, frankly idiotic design decisions like "Let's install updates and refuse to turn off for ten minutes, regardless of whether this laptop needs to be shoved into a backpack right now".
The main difficulty in desktop Linux is hardware compatibility stuff, but IME that mostly boils down to a couple careful decisions right at the beginning. I've had something like four Thinkpads over the last ~10 years and I've yet to have hardware problems of any significance. People occasionally comment that it's ridiculous to have to constrain one's hardware choices based on the OS they want to use, but that's pretty much exactly what many people do for Macs, so I don't think it's all that weird (and certainly worth it).
The Linux desktop is different than Windows 10 or the MacOS, but it isn't harder, IMO.
Not to mention compatibility issues and other general issues.
The Windows command line ecosystem was a stagnant ghetto for a long time.
You had to use an uncomfortable and ugly program to access it and the environment itself barely moved from DOS.
PowerShell was the first real progress in a long time and now they've arrived at 'lets just run bash on windows'.
Linux usability can actually be pretty good, but it's dependent on familiarity, the desktop environment, the distro, the choice of installed applications; everything is customizable, and making most of that customization requires a willingness to research, understand, tinker.
An iPad is locked down to the point of hurting usability, the 'share' system is vastly inferior to Android's 'intents', split-screen mode just recently arrived, mouse support is intentionally missing. Trying to use it as a desktop replacement is borderline masochism. Frankly, it's nothing like desktop Linux, even if you're in an unfamiliar desktop environment.