I don't use that anymore, as Peni said it's been superseded by the updated Gussy up. It checks clothes, 'buys' clothes, plans clothes, change appearance, buy jewelry and cosmetic surgery. It even does toddlers now.

When a sim has a want to actually buy clothes I might go to a shop or might have them buy online on Monique's computer. They do actually spend money when buying things that way and its quite realistic apart from the instant materialization of whatever they have bought. I wouldn't mind if they had to wait a few hours for a delivery van to arrive with their on line shopping items. I myself do a lot of online shopping, so I don't see why sims wouldn't.

Because I mostly play integrated hoods and a playable sim will own and run at least one clothing store, I do try and send them there as well. I am playing my Uber hood now and even that has 1 sim owned clothing store, run by Dina.

If you don't want it to be extinct then bring it back and set some rules. I have seen people who only allow one set of free clothes on age up. Or they fill the buy clothes want either like me online or by going to a store. I keep in mind if the sim is too busy to go out, for example Jennifer Burb was going nowhere but to work while her quads were toddlers, yet she often wanted new clothes. They were probably stained poor thing and she needed to feel good about her appearance. Online shopping, the go to of many a busy parent! But a sim who has a day off and no potty chasing? Off to the store I send them.

One way of ensuring more clothes are bought at physical stores is adding the ability on the community lots you often send your sims to. For example I added a rack at the Pleasantview pool when I made it over. That's a place that sees a lot of use so the rack is handy.
If the answer to that is "I don't send them to community lots very often",maybe the 'issue' (play how you want, but if you are playing in a way that isn't making you happy) goes further to them not getting out to be able to buy the clothes. In which case placing racks won't do much and you might need to see why you don't take them out more.

In my game, playables are entitled to one free clothing purchase though Christianlov's gussy-up after aging. Otherwise, they purchase them normally.