Somehow it doesn't seem possible to prevent HTC from building one smartphone and sell it either themselves or via another brand as an android phone, while at the same time selling the same design (screen peripherals etc) with some minor chages, maybe a slightly different SoC, to someone who wants to sell a phone with a different OS? How exactly would the license forbid it?
Obviously google owns the license and can probably unilaterally revoke it for anything they see as unpleasant (such as building OEM phones that run linux, instead of just TVs that do?) - but is this really expressed explicitly in their agreement? How?
It is the other way around companies that produce Google Android phones (with play store) are banned from producing anything Android not based on Googles stack. Amazon had to find out the hard way that basing your OS on Android makes it hard to find a manufacturer.
Of course this is not globally true. Various countries already informed Google just what they thought of that kind of licensing abuse. That led to Google carving out new licensing regions for every lawsuit and outright boycotting Turkey when they mandated the same treatment as the EU.