Because I choose my phone based on hundreds of different factors.
Whether it can use uBlock is just one factor.
Other phones have their own downsides.
Care to elaborate what is so wrong with it?
It doesn't allow you to use the full version of uBlock.
No sideloading, forced safari, locked os apis to cripple 3rd party accessories and apps (like watches or cloud software), updates crippling performance, massive number of bugs, especially if you don't use iCloud (i lost data multiple times after the update), to mention a few.