Really Motorola doesn't need to sell a GOS phone. Motorola just need to sell a phone with the right hardware security features, open source/upstream their Android/Linux patches, and give users the ability to run GOS.
Hopefully they can then give you the option to buy one with GOS preinstalled, but even if they don't. It will be sufficient that it can run GOS.
Unlike Windows, nobody feels they're paying an inherent tax when buying a stock Android phone. I'm sure nobody will mind.
The hard part will be actually supporting the phone for long enough.
GOS is reliant on Google's open sourced Pixel android releases up to and including the 9 series. This is because GOS doesn't have the resources to handle that entire side of things. But I guess part of that is also that GOS doesn't have access to the necessary information to do that stuff properly either.
This is a power move on Motorola's side, and I'm here for it.
There are conditions for OEM's installing any of the Google services. Although, so far it seems that graphene have been able to work around them (although, this is not a world I traverse).
I don't think the standard Android user wants to install ReVanced. They don't care about custom OS's. They want support and updates.
I remember the dark times where you purchased hardware, and you would be lucky to get 4 years of updates.
Motorola/Lenovo are late to this game. Two years ago, people updated to phones with phones that would get monthly security updates for five years. This was new to the Android ecosystem two years ago (with the exception of maybe a few Pixel phones).