I do not extreme coupon, but I do coupon as much as I can. I do agree that the people on the show are the extreme of the extreme and I could not and would not want to have the stockpiles that don't even fit in the house, LOL!
However, that said, I do think that couponing and stockpiling is a way of thinking that some people get and others don't. To truly get the best prices, you do need to build a stockpile to some degree so that you are never paying full price for items you use. Of course, you can't do this with most perishable items, but you can do it with a lot of items. This is why couponers stock up when they can. For example, we go thru a ton of ketchup. If I get a good deal (free or close to free), I'll buy enough for a year or more, depending on the expiration date. Once you build a stockpile, you never have to pay full price which frees up your money for perishables (fruits, veggies, milk, etc).
Also, what many people don't realize is how much of their weekly or monthly "food" budget is actually being spent on cleaning products, paper products, health and beauty products, etc. Once you stop paying for items like shampoo, deodorant, toothpaste, soap, cleaning products, dish soap, etc, you'd be surprised at how much extra money you have to spend on actual food. I've had many people tell me that they don't find coupons for the fresh healthy foods that they eat. I agree that healthy food coupons are harder to come by, but just cutting out the cost of non-food products would greatly reduce most people's grocery bill. Everyone I know uses toothpaste, deodorant, shampoo, soap, etc. I haven't paid for that stuff in years due to stocking up when I can get it for free. I don't have 50 toothpastes in my house, but I do keep 8-10 on hand at all times. Never run out, never pay for it (thanks mostly to CVS).
Our supermarkets don't do "overage" either. However, you can still find money maker deals every so often. For example, at shoprite this week, a $4 catalina coupon was printing out at the register for buying 4 reach toothbrushes. I purchased 4 toothbrushes for 99 cents each and used a dollar off coupon for each one which made them free. However, the $4 off my next shopping order coupon still printed out at the register so now I have $4 to apply to real food next week. I also purchased two bottles of folic acid which were $2.19 each and used a $3 off 2 coupon. Therefore, I paid $1.38 for both. However, at the register, I received a $3 off my next order coupon. So, I actually made $1.62 which can be applied to real food next week.
It does take time to coupon, but for many sahm's, it is a great way to help out financially without having to put their children in daycare. I couldn't let myself get to the point of storing stockpiles in the bathtub though, LOL!