I like to look at websites that offer "last season" outdoor gear at discounted prices. The major frustration is that the sizes are never my size of shoe/shirt/etc because the popular sizes are gone sooner than the odd sizes.

There is no "domain-specific" improvement (The "domain" in this case being "last season discount retailer.") to the basic shopping cart ecommerce experience that would give me a way to flag my interested product or product category so that I could be notified when the item is in-stock.

This basic feature would vastly improve my interaction with the websites and would probably result in higher sales.

In today's world, that's a huge ask to have that kind of feature implemented.

Heck, even asking for a good "syntaxable" search seems to be an impossible ask. Imagine being able to search "Category: Shoes; Brand: "North Face"; Price: >50&&<120"

The fact that this is never implemented yet billions of dollars are poured into ecommerce development kinda reflects how the industry is focused on improving the tooling/back end and not the design.

I see vastly more posts in this vein: "Nobody really knows how this complicated spaghetti-like system works"

than in this vein: "X tool allowed us to build a Maserati of our domain."