There's one group of Android users Google's new sideloading rules won't affect
(www.androidauthority.com)
I do not understand this statement.
You mean if it's not possible to easily sideload apps, people won't buy premium android phones?
Because if that's the reason, iPhones would be a massive failure.
If everyone in the world was like me and you, yes, the most popular phone would be the fairphone and maybe they would even sell it with a Linux ROM, while iPhones and other phones with locked bootloaders would be impossible to sell even at 95% discount, but we account for the 0.0001%