My 2cents....
I
do eat a balanced, nutritious varied diet. Here's just a sample of the different things I usually eat in an average week, every week:
Capsicum (red, green and often orange)
Broccoli
Brussel Sprouts or green beans
Pumpkin
Potatoes
Carrot
Dark-leafy lettuce, or baby spinach leaves
Celery
Tomatoes (lots)
Cucumber
Snow Peas
Mushrooms
Onion, spring onion, garlic, herbs
Oranges
Apples
Bananas
Strawberries or Blueberries
Rockmelon
Cashews, almonds
Oats
Wholegrain Bread
Avocado
Salmon
Olive Oil
Fish
Lean red meat - top grade steak or lamb
Tuna (lots of)
Rice - basmati
Pasta
Cous Cous
Kidney Beans or Chick peas
Low-fat yogurt
Low-fat milk
Tofu (occasionally)
.... yes, I would usually buy ALL of these things in my average weekly shop. (My shopping is v. expensive!!

). And I have lots of time to cook. And I do. I bring salads every day to work, cook a homecooked meal every night, except weekends, which are my naughty times.
So you could say, in effect, I'm close to ideal.
But I STILL endorse supplements. For starters, I don't know how much nutritional value is actually in the food I'm eating. I know it's good, but how many vitamins, how much RDI am I getting? You'd have to be a nutritional scientist to work it out. I am a smoker, so I need to be careful of my Vitamin C levels (smokers need twice as much). Who knows if I'm actually balancing it out? I'd prefer to be safe. Also, I take extra fish oil capsules because I believe that even with the tuna and salmon I manage to fit into in my diet, I'm probably not getting enough to balance out the Omega3 deficit we usually have in our diets. I dread to think how people who don't eat fish at all can manage.
I drink alchohol. I'm not giving that up any time soon.

That leeches vitamins from the system too (mainly B, which is my desert island essential ). So you see, supplements have a place in even good diets, I think... let alone ones where people have a 1/4 of the variety I get in mine.
That said, I *don't* take antioxidants or a multivitamin; purely because I eat so much tomato, berries, fruit and red capsicum that I figure I don't need to. But for most people who have broccoli dying in their fridge while they're still at work at 9pm at night, it's almost essential. Ditto for people who are actually trying to get a therapeutic benefit (ie. overcoming disease/ preventing glaucoma etc) rather than just a maintenance one.
I reckon we could all make a little bit more of an effort if we really tried, but supplements are a good way of making up a shortfall. I'm not recommending going silly and spending your whole week's wages on expensive stuff... but if people feel it benefits them and it fits their lifestyle better, or fulfills certain needs foods cannot, I don't see the harm.
