It depends on what you shoot, but microfocus issues with dslr's is a well understood and accepted reality when shooting at fast apertures. If this were not an issue, microfocus adjustments, and all these microfocus softwares would not exist.
There is no microfocus adjust feature in mirrorless bodies because it's an issue that does not exist when the AF system is part of the image sensor itself
Not completely true, when adapting 43 lenses with an E-M1/E-M1ii it's pretty common to have to microadjust the lens as Olympus doesn't use a CDAF finishing step like with m43 lenses. Sony has a similar CDAF finishing step when shooting S-AF.