Ladies upper bits and Men’s Down bits.

I’m very interested to know why men’s underpants haven’t got the same sizing system as ladies brassieres. As all ladies upper bits are in different sizes ( cup sizes AAA to infinity) – am I right in thinking all men’s down bits are of differing sizes also? If thats the case, lets bring out the new sizing system for men’ pants , called say “mug size A to G” Would ┬ámen be more comfortable with this improvement? What do you think?