Not in my experience. I did an non-clean upgrade and found Edge was the default browser. And then when I did a clean upgrade with only IE11 as the default brows

Not in my experience. I did an non-clean upgrade and found Edge was the default browser. And then when I did a clean upgrade with only IE11 as the default browser I believe it defaulted to IE11 for some reason. So, I think there is some legitimate shenanigans going on here. If the W10 upgrade scripts can infer that I previously had IE11 during my clean upgrade and keep it as the default then it should do the same with any other application preferences. Most likely the devs were being lazy and possibly paranoid that the initial experience with Windows 10 would be terrible if the application preferences were maintained. But that's just my guess.