the tv show tonight blames the young ones (why? i find it funny)
personally i blame the over zealous introduction of canned laughter that pretty much ruined red dwarf and various other sitcoms for me.
also american writers got far better than the english writers (friends, seinfield, frasier in the 90's compared with my hero,my family, brittas empire and various other average to crap sitcoms from the same (ish) period)