There are too many reasons why this is wrong, so I am not going to list them all. But one is network effect. If friends own an iPhone, you are going to buy an iPhone too because then you can use Facetime, etc. Another is simply the fact that people don't know what they want, and they assume the vendor offers what is best for them. A third reason is that any phone has many cons and pros, so "best" is not well defined, and a regulator might as well try to regulate towards more pros and less cons.