2Perhaps that, but also because everyone seems to have lounge access these days. Business class lounges are essentially economy class lounges, and first class, business. Very few lounges offer genuine restricted access to class of service, those that do - Thai F, Lufthansa F, SQ TPR, perhaps even the Concorde Room... still offer some glimpses of what lounges used to be like.
I guess it depends what you value in a lounge doesn't it. IE if you value a quiet space without a crowd then yeah the fact every man and their dog seem to have lounge access these days really does devalue it a bit. I guess you could also blame that for the general availability of food/drinks - IE the less people that have access, the less food/drink that would be consumed thus you could afford to put on a higher quality - whether that would actually happen though..
To me though - airports are now almost a destination in themselves - especially the larger ones like Changi where there's lots to see and do at the terminal itself. Gone are the days of sitting at a gate for hours with nothing but expensive duty free shops available to you.