You can always find ways to monetise an operating system. Some possibilities include: * add products/referral links to os search results (like ubuntu lenses)

You can always find ways to monetise an operating system. Some possibilities include: * add products/referral links to os search results (like ubuntu lenses) * add ads to the base operating system (like kindle's sponsored homescreen) * sell spots for default search providers (like bing for siri) And you target old phones by providing them with an upgrade path to cyanogen mod based on a more modern android version. Many devices are technically fully capable of running modern android versions but have been abandoned by their manufacturers.