Then the solution is not for Shimano to enforce MAP overseas, but to instead stop enforcing it in the States. "MAP loopholes" haven't killed your business, MAP has.
They should simply sell parts at competitive costs, but price labor for repairs, adjustments, etc. at a fair rate.
Alternatively, charge a transparent markup in exchange for “free” service on the item should something go wrong.
Where MAP fails is if brands want to different prices globally. This is because items will just get re-imported if they are priced lower in other countries. They want the benefits of globalization which is cheaper labor and materials but don't want to negative aspects which is the same price globally for the product.
Still, feel you on the retail apocalypse, and how every other new internet darling can somehow skirt taxes or... and the problem is unfixable until right after it doesn't matter anymore. It took something like twenty years for Amazon to start paying US sales taxes most of the time, in many cities Uber's business model was price dumping etc.
Shimano could, were they willing, use Parallel Import laws to prevent European retailers from selling those products in the American market. They've chosen not to. So whether one likes hearing it called a "refusal" or not, I think that's what it is.
Seems like addressing this problem is important. Why is wholesale cheaper in Europe than the US?