I can't tell if the icons get larger as you hover. That sort of magnifies this problem, as the start button would shift left as other icons are highlighted.
I think you're comparing apples and oranges though - with web pages, the issues are readability and aesthetics, whereas with the taskbar it's that icons are where you expect them to be (when centred, they will move as you open more windows).
IMO, a more apt comparison is the tabs of a browser, rather than the content the browser is showing.
If you have such a large screen that you can't quickly move your pointer to anywhere on it, I suggest that you have a bigger problem with your system than where your Start menu appears.
Fun fact btw, in win 95 the border of the start button was not clickable, so slamming into the corner did not work because of that 2px border. Microsoft was proud of presenting this feature in later versions, don't remember if it was in 98, 2000 or XP.
Everybody except hn readers who live in their own bubble.
There's a name for that: https://en.wikipedia.org/wiki/Fitts%27s_law
and the fact that their UI people somehow have forgotten about it speaks volumes.