I'm pretty confident the government will ensure that the DIY community will be at end of the line for any Grp III products - I could be wrong. It only makes sense - I don't think consumers who can't get much of anything else (due to the inherent transportation constraints) won't be too worried about any shortages of motor oil. Look,consumers could always go to synthetic blends, if it comes to that.OTOH, commercial and government fleet buyers are contracted at low margins.
They do undoubtedly represent a much greater volume collectively then would retail sales.
Still, rationing by price is a reality so I would expect blenders to give priority to the higher value markets.
There are good Grp II bases available for heavy duty truck engine oils, so it may not be a matter of supplying one or the other but more a matter of adequate Grp III supplies drying up.
I suspect that the Grp III based PCOM oils are probably going to be constrained for fleet buyers as much as they are for anyone else and the supply contracts probably include provisions for potential basestock supply shortages.
We may see a widespread resurgence in Grp II based PCMOs.