I work on an embedded Linux device. Sometimes, we do whatever nasty hack we need to make this kernel work on that device -- but those changes aren't portable,

I work on an embedded Linux device. Sometimes, we do whatever nasty hack we need to make this kernel work on that device -- but those changes aren't portable, aren't maintainable, and don't meet the quality requirements to be in the upstream tree. There can also be a perception it's "a waste of time" since "nobody will run another kernel on this anyways"