Actually, for a bit of factual accuracy Air Exel operated Maastricht from STN for many years, ceasing in the post-9/11 full service apocalypse.
Comparing with RTM is ridiculous, RTM is on the doorstep of AMS in a completely different part of the country. It's like saying a route to Newcastle wouldn't work because one to Liverpool wasn't too popular.
FR fly to Maastricht, but with timings that aren't too business friendly.