Novalissoide
Yes, but only 6 billion have a smartphone, the western countries are saturated and the African and Indian customers who don't have one yet prefer the low price range.
Globally the flagship market is 18% of all sales in 2025. The biggest sellers there are Apple and Samsung.
In Motorola's case we talk about sold units in the thousands, not millions. Apple and Samsung have millions, but still much less than their lower prices models.
How many of the Motorola flagship owners might want to use Graphene OS? Realistically it won't be more than a few hundreds. Because overall there aren't many.
Even on Pixels where you could install it on used Pixels you can buy for 150-200$ the market share of Graphene is some thousand users.
How could it be more on a 1k phone?