Perhaps some women have put on weight with staying at home bored, and eating more than normal, lack of exercise. But I agree, big bouncers can look a bit ungainly. Or they've shoved some large Easter eggs up their jumper!
Its because most bras now are padded which is very awkward for naturally big busted woman who dont want padding as most dont want to look any bigger in the bust. Also high neck tops make a womans bust look bigger if she is already well endowed as they normally wear v necks or low cut tops to prevent looking even bigger which not many of these tops or dresses are about now.