First point, this is a new rule.  This is not "same old, same old", it's a brand new rule.  The old "reciprocity" rule that if you were legal at home, you were legal everywhere in North Americal has been broken and will no longer apply.  There are many vehicles that people drive every day in Canada with a base level license that could drive those vehicles legally in the US, but after July 1 cannot.
Second point.  Don't assume that your use of your RV is the same as MY use of MY RV.  I have in the past, and may in the future, use my RV in a manner that would make in commercial.  Example - taking used race car parts to a race to sell in a flea market.  Towing a race car for a friend and getting paid to do it.  Lots of people who might read this forum use their RV's in a manner that could be considered commercial.
Third point.  This is a change by the US FMCSA agency, nothing to do with any Canadian agency in any way.
Fourth point.  I don't have much of an idea on this one.  There is no option in any Canadian province I am aware of to even get a medical examination endorsement on a base level license.  People who figure this out and need to get legal will either have to get a commercial license (like a bus, truck or ambulance license in Canada) or get a US medical examination per that link I posted in the original post.
BTW, I got the official letter from the government because I hold a commercial license in Nova Scotia, so I get considered a "commercial carrier". It laid out the issue in precise detail, included the relevant US regulation wording and had references, so I'm just passing on the information, no guessing at all.  This will hit professional drivers, because lots of real commercial carriers hire people with base level licenses to drive delivery vans, taxis, and things similar that go into the US all the time.  
Brian