I think that's a little unfair. Look at animation in the 60's - especially the limited animation of Hanna Barbera. The Flitstones was a prime-time series, but the animation is not that much more advanced than the (deliberately) poor cut-out look of South Park. And wait until you see the animation on the '67 Spider-Man set - you're lucky if a mouth moves!
Actually you kinda hit on a point i failed to mention. To me the 60's and 70's were an era when animation seemed to go down, from its peak in the 40's and 50's. To me we are in a similar era. I dont even count south park as animation {besides the majority of it is past on computers now anyway}. And the '67 spiderman series was nearly 40 years ago, i'd hope to heaven we've come somewhere from there. But at the same time you can see the effort isnt there on a lot of shows. compare say lilo and stitch or recess to ducktales or talespin. take extreme ghostbusters and compare it to the real ghostbusters, etc. The vast majority of it has been simplified for artists.
Even in the 70's, when animation improved, it was still far from the quality of television animation today.
We live in a good time for tv animation - we have shows like The Powerpuff Girls, which, while limited, does have amazing visual styling, shows like The Wild Thornberrys which, despite the odd character designs putting some people off, does have quite impressive animation, and even the new What's New Scooby Doo? blows away the animation of older Scooby Doo episodes.
to me that is a matter of taste. the image looking crisp is more a reflection of technology and a lack of aging on the film, more so that actual hand drawn style. the power puff girls to me is exactly the style of todays animation i cant stand. very angled, very shapely. essentially the style is easily drawn because its kinda like connecting a bunch of shapes together. i had a family friend who is an artist who used to work over at warner brothers and he said the biggest problem they started having is many of todays artists really cant draw anymore. they are used to computers and other tools covering up their mistakes and which push comes to shove they have a very difficult time time copying a style guide. power puff girls, many of todays shows are very simplified to reflect that. many scenes are used several times with varying backgrounds. many designs are simple "connect this shape to that one" so that EVERY episode looks the same. there very angled because an increasing number of artists are seriously struggling to do circles. heck even the simpsons nowadays is primarily done on computers to make sure the drawings are rounded, a lot of their newer artists simply cannot draw the style anymore.
While none of the television animation of today compares with a Disney Feature animation movie, it is vastly superior to any creditable television animation before it (ignoring crap like Ultimate Muscle). And in my mind this is one of the reasons traditional animated movies have suffered - Disney until the mid 80's didn't really have any televised competition, but now anyone can turn the television on 24 hours a day, 7 days a week and see adaquate animation - and to the average person on the street what we see as adequate, they see as good. If people blame the handful of DTVs so much, the influence of constant television cartoons must be many times greater.
For me TV is much like music. people will consume WHATEVER you put out there. it doesnt matter if it all looks the same, sounds the same or sucks altogether.people are gonna buy it and love it and defend it. for my money the best animation in the world right now is coming out of japan. i am not an anime fan by any stretch but their blend of animation and computers is second to none. the reason the u.s. hasnt switched over to it? too much money. thus you're gonna get more recess and more invader zim and more animation that looks increasingly like someone's sketch pads and less like a finished product.
a simple test is this, take a look at the backgrounds. take a look at the realism of say ducktales season one and then compare it to even darkwing duck. take a look at launchpad and you can see which one took longer to draw.
it comes in spurts much like music. there are era's where much more effort is put into product and there are era's when if you've seen one you've seen most.
i tend to think when you hold shows side by side it becomes more apparent and if you can ran the numbers on cost/time spent and number of frames of most tv cartoons you'll see that each of those categories have steadily declined in recent years. it probably peaked in the 80's with shows like the muppet babies, ducktales and a few others, and it's steadily gone down since. saturday morning cartoons are almost unheard of since 1995 and many of today's saturday morning cartoons are simply shows that were run during the week anyway.
looking at the numbers now compared to 20 years ago also supports this argument. channels like toon disney have made a fortune off slapping together fast cartoons and marketing the heck out of them. Really what choice do viewers have? if you dont like what is playing on toon disney where else you gonna turn? cartoon network? there's few syndicated shows, little or no saturday competition and tough cartoon making is easier than ever, there are fewer people making quality cartoons.
think about all your options you had to watch on saturday morning 1991. now compare it to 2004. which generation had the most options and as a result of that competition that better programming. it's not to say that everything out today is crap, the goods are just a lot fewer and farther between. when a show couldnt beat out another show for ratings it was replaced with something better {in theory} but who is toon disney competing against? cbs, nbc and abc run news programs or talk shows now. heck abc is owned by disney which knocks them out of the running. that leaves two channels for the most part and if you don't have cable you can rub them out of the equation too. when someone isnt pressed to get better, they get lazy. happens in any industry, any where. from animation to wrestling, competition makes the product better. there is no competition right now and the product reflects that.
I was shocked really. I thought they would take them down by now, but the only old one I REALLY watched they took down was The adventures of sonic the hedgehog. they used to show that at 7:00 AM and I used to get up and watch it. 
