Speaking as an android app dev there are some challenges but your instinct is right. I've rarely run into device specific issues, android has decent support for

Speaking as an android app dev there are some challenges but your instinct is right. I've rarely run into device specific issues, android has decent support for building flexible layouts, there are official libraries for bringing some newer version ui components to older versions, etc. Overall while certainly more challenging than writing for a single known device its not dramatically difficult at least for basic apps.