To be fair, there are alot of time intensive courses out there for training. It doesn't mean they're bad, just that the quality would again be dependant on the person who learnt and is now teaching.
Muay Thai, can be taught in it's entirety in a very short period from a technical sense. Hell I can show you all the nuances of Muay Thai in a day but you probably wouldn't retain any of it. But that's the key...is it enough time for the person to to retain it well enough to teach it at even the standard level of quality?
Sometimes yes, sometmes no. But the same can be said of people that learn it over ten years.
"I don't know if anyone is known with the art of "sitting on your couch" here, but in my eyes it is also to be a martial art.
It is the art of avoiding dangerous situations. It helps you to avoid a dangerous situation by not actually being there. So lets say there is a dangerous situation going on somewhere other than your couch. You are safely seated on your couch so you have in a nutshell "difused" the situation."