Earlier quoted context omitted.
What makes you think this is unique to Chinese tech companies? Windows 11 put ads in our start menu.
do you mean putting Bing on the start menu? Microsoft just made them opt-in by default and hoped that folks won't notice or care. you can disable them. for Chinese devices, there's no way to disable them. the difference is, for Windows, having Bing on start was a feature (although a bad one). for Chinese devices, you just get ads - you're stuck with ads while changing your brightness.
And as other commenters have pointed out, lots of budget phones and hardware jam ads all over the place.
Premium hardware too (hello Smart TVs)