One could, but the competitiveness of low-end Android makes that pretty implausible; people buying a cheap no-name Android who replace it with another cheap no-name Android are unlikely to get that from the same company.
It's implausible that it would be for market control purposes, because no one player controls that market and competition is intense (unlike Apple's situation). If no-one's offering support in the low end it's because doing so is uneconomic in itself, not to create an effect in another part of the ecosystem.