Nobody (aside from the US Government, obviously) really cares enough to buy hardware without a management engine, so why put the effort into writing and testing

Nobody (aside from the US Government, obviously) really cares enough to buy hardware without a management engine, so why put the effort into writing and testing a configuration that a tiny segment of the population will use? (Also, Intel AMT contains some functionality that is actually used by the OS in everyday use, and turning it off would break that.)