^99 cent stores today are 99 cents and up stores. Heck, I picked up a portable closet years ago at a 99 cent store.
I've never noticed dead 99 cent stores. It's rare there's a huge crowd, but there's usually a couple customers there when I go to on, which is often. I regularly buy toothpaste, toilet paper, paper towels, toiletries, and household items at the 99 cent stores. I'll usually take a quick tour to see if there's anything that's a really good deal. You'd be surprised what turns up at 99 cent stores. The items there aren't going to be the most beautiful, but they'll do the job. Don't buy a screw driver at the 99 cent store, but do buy your coaxial cable and digital converter for an old TV there.
Items in my home that come from a 99 cent store: aluminum sauce pan we use to fry food; christmas lights; christmas decorations from my first christmas in my own place; a small plastic bucket with a lid to put cat food in; a pitcher; coaxial cable; deodorant; a shot glass; drinking glasses; baby oil; a big tub of off brand petroleum jelly that I've had for over a decade and literally cost 99 cents; a shower curtain liner; blue plastic recycling bags; a napkin holder; flower pots; and loads more. When times are tough and I've have to find ways to cut back, the cheap body lotion and White Rain shampoo are better than nothing!
There's so much that I and others can and do buy at the 99 cent store - which is closer to me than a drug store or home good stores - that their financial viability isn't something I question.