Google is (a) restricting "Android" functionality through trademark and software licenses with manufacturers and (b) paying the manufacturers, e.g., through placement agreements and revenue sharing agreements
Given Google's actions in this regard, why would a manufacturer want to allow hardware purchasers to remove Android and install an OS of their own choosing, e.g., one that does not enable Google data collection, surveillance and ad services and generates no revenue for the manufacturer
The idea of regulating manufacturers that partner with Google seems far-fetched, not serious. For example, I don't see HN comments suggesting Apple should be prohibited from interfering with buyers who want to remove iOS and install another OS in its place
Meanwhile the control, privacy, etc. problems with these corporate OS are avoidable right now by choosing different hardware, specifically hardware that allows installation of open source OS that a concerned buyer can edit, compile and install themselves