The answer to theft isn’t really just locking everything behind glass. That means anytime someone wants something you need to find the person with the key. That means having at minimum, a part timer with experience to be on call to unlock sections on demand. And unless you increase the amount of workers you have per shift there is no way you can meet customer demand.

And locking up the high theft stuff only means they switch targets to non locked behind glass stuff. I have direct experience with this.

We moved the high theft stuff away behind glass and lo and behold the same guys come back next day and they just stuff their back packs full of non high theft stuff and run out the door anyhow.

Theft is just a part of doing business. Between shop lifters or stealing off of the delivery truck. it’s not possible to fully stop.