Yes, some of those coupons can be found. Just not every week, there are coupon “seasons”. You also need to look in stores for tear pad coupons or on product coupons.
The whole point of extreme couponing is to use a LOT of coupons to stockpile items you use. I mainly got free shampoo/toothpaste/toothbrushes, but after 2 years the stockpile is nearly gone. When you get toiletries for free (or they pay you to take them), it eases the food budget.
You don’t need a huge stockpile. I have enough BO sticks to last me until next summer and I know there will be more coupons for the same item again before that when I can get more. Ditto the toothpaste and about everything else. No need to get 10 years worth of stuff. Too much space taken up.