I agree that a large choice flies in the face of sustainability but even your beloved paramo has a large selection. Some are unbelievable though (I just counted 80 different jackets from Mammut, mind that does include softshells, vests, down jackets and all types of waterproofs) which does seem to be a rediculous amount.
I am not sure I understand the logic behind your point about recycled fleece. Surely what matters is whether or not it is sustainable and environmentally better than a new fleece, no? I think you are right that there are some marketing in the green labelling of products but I think that some brands do take it serious. Usually it is a cost to them to source greener materials and manufacturers so actually it would be in their interest to NOT do it.
As for Paramo, sure they have a good design, but I don't think they are the best (but that is another topic). Their design may remain unchanged but that doesn't mean that they don't make a lot of them! Most people don't change their jacket because it doesnt work anymore or there is something wrong with it. They change it because they want something new or a better technology or a different fabric. Longivity I don't think is the major driver in people buying a specific brand. Are they more environmentally friendly at Buffalo and Paramo? I don't know but I do wonder how much of the Nikwax sales (and consequently flushed down the drain) and use they are responsible for.
I think that manufacturers who make an effort should be applauded for doing it... if it is indeed genuine.