It's not just about having tech inclined staff, but just the whole staffing strategy in general. Most grocery stores et. al. try to staff as cheaply as possible and try to have their workers do as much as possible during their shift. This means that there's no extra time available that they're not shelving products, or sitting at the register.

Rather than have extra staff at the store to do stuff like monitor fridge performance, it's better to have them report stuff centrally and have someone or some tool monitoring thousands of fridges across the entire chain. This way you can send out repair teams and plan maintenance more efficiently.

We all have fridges in our homes.

Why would managing fridge temps be a job that requires more than a few minutes a day at most ?

How hard could it be ?

There is a video game where you can unlock a thermostat which grants you extra points if you go back to it and readjust the temperature once in a while. Everyone hated it and kept mentioning just how ludicrous it is that a device called a "Thermal Static" somehow works by inputting thermal changes as opposed to thermal targets, prompting the developer to agree that was the stupidest idea they had and they would be changing it.

This game is nsfw.

Are you implying french fridge makers in real life are stupider than porn?