Best guess: someone or some group wanted to rewrite the Taskbar "from scratch" because of "all the tech debt crud making it a tough codebase to work in" and well a lot of that "tech debt" was all the stuff that made it customizable and supported drag-and-drop and all sorts of other things that users use every day but makes for a complicated codebase.
This - my theory is that there's a cadre of middle managers at Microsoft who are jealous of Apple, and express this as a persistent and pernicious trend toward imitating Apple "features." Not sure I've ever seen a single good thing come from the "user experience" crowd - sorry, you don't know better, gtfo my desktop.
I have more than once accidentally moved the task bar. It causes a moment of panic until I remember that I can just move it back. And I'm a rather computer-literate person. For someone who is not a computer person, they could see this as "I broke it" and have no idea what to do, or even if they can continue to use the computer.
It is Microsoft™ Logic®. It a variable can have only 2 states, with Microsoft™ Logic® you can have this variable in a third state which makes everyone look stoopid.
