You might just live in crime central, that's not happening everywhere. Probably on an individual cost of cashier versus lost stock basis with each location.

I sense a lot of dislike for self-checkouts and wonder why they are done so poorly where other people live. In Holland they are fine. You can self-scan with either a portable scanner or your phone while you shop, or scan the items at checkout. I've literally never had to wait for a free machine, and they work well. Some people use the registers with humans scanning for you, and they seem fine too.

There's a fairly big shoppers drugmart I went to in north Vancouver and they only have self checkout and one customer service desk. Most people still hate them from the moaning and groaning you hear while waiting in line though.