Weight training has similar effects. The body can be in an anabolic mode with a caloric surplus, and in that case, yes it's good to work hard in the gym. (Most people shouldn't go to failure very often if ever though.) But when you are in a catabolic mode, working out very hard with weights is going to lead to adherence issues again, e.g. dreading the workouts. You don't really need to do all that much to maintain muscle mass, as opposed to building it when you are approaching your genetic limit. Three times in the gym per week at 30-45 minutes per session would be just fine in my opinion.
In summary, picking something you can adhere to is far more important than trying to optimize the equations in a way that someone with infinite willpower might manage.
My issue is not length, but intensity. I understood "not doing too much in the gym" to mean "don't work too hard." If instead you meant use your time in the gym wisely, then that I agree with. But if you want to see continued improvement, then you need to increase the intensity over time. Despite being in the gym the same amount as some people, I'm in better shape because I work harder.
I agree with your summary, but I would stress "work hard." I've found that working hard and continually trying to improve actually makes workouts more fun.
There's a time for intensity. As someone starts to get diminishing returns, the needs increase for higher intensity, probably higher volume, and higher complexity e.g. periodization or something even more complicated than that. The time for intensity is not when you are just starting weight training, in which case anything will work (but someone should do exercises properly of course.) The time for intensity is doubly not when your primarily goal is to lose weight, in which case the body isn't going to have its full resources to repair itself.
As a counter-example to what you said about intensity, check out the video for The Captain: http://www.gymjones.com/video.php
I also like this essay: http://www.gymjones.com/knowledge.php?id=36