I don’t doubt what you’ve experienced, but I hesitate at drawing conclusions from a few samples. There are many, many different processes and systems out there, with multiple opportunities for error to creep in.
In my experience (two decades of working retail for several companies), inventory discrepancies can have many causes, not just shoplifting. Inventory software is a major factor. Some systems will load an entire shipment into inventory even if only part of it gets to the store, creating inaccuracies. Packing mis-ships happen too. A store might get boxes meant for a neighboring location, or somewhere two states away, and if it isn’t caught during the receiving process, figures will be off. And if a system update doesn’t play nicely with a store’s hardware, chaos can result.
I worked for a large company (which collapsed into bankruptcy many years ago.) They rolled out a new inventory system chain-wide, but didn’t realize that it wouldn’t work with a specific hardware build. Over 400 stores, mine included, were affected, and our computer listing rapidly became wildly inaccurate. All I could do was tell customers, “I’m sorry, I can’t look it up, our systems are broken. It will be faster for me to check all the places your item can be than the time it will take to fight with the programming.” Several patches and four full-store inventories later, it was fixed (mostly), but it took months, and it was a major headache for everyone concerned, especially employees.
Most store employees will do their best for their customers, despite the low wages, management pressures and mistreatment, and abuse from the general public that can make the job resemble certain circles of hell. But your average worker has little impact or control over inventory and ordering systems, especially when the vast majority of requisitions are made from a home office (or worse, an outside vendor) that has little-to-no experience with the day-to-day functioning of a store. If you want the best customer service experience, it’s advisable to treat workers with compassion and kindness. It’s not an easy job to do, and putting more obstacles in the worker’s path by heaping anger and frustration on them will only make it harder (if not impossible) for customers to get what they want.