I look at it anotherway!...All that build up of varnish/crap is stuck to the inside of the engine, It is not doing any harm, so why disturb it? Why try to get it circulating back in the oil to go through the system..... Do you vacuum the top of the ceiling inside your house roof cavity?... Do you polish the underside of the vehicle you are so fussy about? ...i doubt it.
The filter is supposed to catch the floaty bits that wear the internals, the bits that doesn't float around just settles harmlessly out of the way, and with correct oil changes there isn't too much of that either.
Instead of rooting around, wasting oil doing 'flushes' , it would be more benificial to do frequent oil/filter changes.
HELL! got that off my chest!....LOL