I don't think Shimano stopped selling online entirely, I think they just stopped selling across regions online. Both of the above vendors are European, they just stopped selling in the US. You will be able to buy Shimano stuff from domestic online sellers. The reason for the ban is Shimano wants to price control by region. Shimano lowered their US pricing by 20-40% in 2016 in anticipation of this change.
I use Ultegra groupsets as a comparison. A full 8000 groupset undiscounted from Merlin in the UK costs about $720 shipped, compared to about $850 undiscounted from a domestic seller. That's a hefty premium in the US no matter how you paint it. At least a shop will now likely be able to sell you Shimano for similar prices now. Also, Ebay is still out there.
Note that SRAM has always set MSPs online.
Last edited by Hiro11; 05-27-19 at 12:47 PM.