Lawrence may well be right, but I also think we tend to look back on "the old days" fondly and the nostalgia sometimes clouds our perspective. Looking through rose coloured stained glass windows is another way of describing it.
We do it with most things in life - for example, today's music is no where near as good as the stuff we listened to when we were teenagers; society used to be more polite; whisky used to taste better, etc, etc.
I'm only hypothesising here, but distilleries probably had a lot more latitude 10-15 years ago than they do today. The recent boom in sales and popularity of single malts has meant that every move a distillery makes is closely scrutinised, and consumers are far more educated and aware than ever before.
Where am I going with this? I think the pressure and competition is really on these days, and distilleries can't afford to put a foot wrong by releasing a dud or being lazy with their vattings.