Damn that's a pretty small particulate size to stop.
I think it has more to do with spectacular improvements in filter media,
than engine requirements.
Probably also has something to do with the 5000 mile oil change recommendation.
That bit of info might convince me that I cannot safely use a filter for 2 oil changes,
if particles 10 microns and 20 microns and larger can clog the filter and impede the flow of oil.
Cigarette smoke particles are around 50 microns, a fingerprint 55 microns.
For sure your drinking water isn't filtered to that quality.
I'll bet there isn't any oil film in the engine that is less than 50 microns thick.
Even 20 or 30 micron particles aren't supposed to be a problem in a 50 micron thick film.
Particulate sizes that small and smaller is why blackened oil is a skin cancer hazard to respect.
Don't get it on you lightly, or think big deal, it is easy to wash off.
Particles that small can go into your skin as easily as a cupful of sand
would penetrate a bucketful of marbles.
I've done some reading on nano-particlates, it's a booming new technology, but be very afraid, materials that were never considered hazardous before, because they could not be readily absorbed, are totally unregulated, even tho' in nano-particate size they can penetrate your skin or lungs as easily as smoke can penetrate a window screen.