So a business is determined viable or not by the ability to spend extra on security staff?
So little old Mrs Smith's quaint antiques shop which she runs as a means to pay the bills and alittle bit of spending money isn't viable because she doesn't have the extra money in the business to pay a security guard to stand there all day and stop people entering who don't have their t-shirts over their faces?
Yes, effectively. They might be viable day to day in normal conditions, don't get me wrong, but not viable when something bad happens, and bad things do happen, that's part of running a business. It's brutal/ awful, I know and it's even worse for high street shops as their market is disappearing by the day, and has been for a long time.
A small shop like that would not likely be getting a great deal of footfall anyway, so I'm pretty sure they could handle the security requirement themselves. It's also not like they're going to be mobbed by young yobs, or 6 foot 2, 40 year old blokes that are hard as nails being awkward. Supermarkets would get those, but they can afford to deal with it.
For us in construction, we have to allow for contingency, rainy days, downtime in work etc, but most don't, that's why most go bust, so that's why they're not viable.