That was my point. Nobody can provide the availability, physical security, and compliance with regulatory standards that Office 365 offers if they are a small business that was the target market for SBS when it was still a product.
Now many people are happy to compromise on their requirements in exchange for converting a monthly cost to a low one-off purchase (or not making the purchase at all if they already have something), that's obviously entirely their decision to make. But when deciding that it's definitely cheaper to have something like SBS I think you need to account for your backup costs, power costs, cooling costs, hardware maintenance cover, cost of your time to patch it (out of hours), cost of future purchases of Exchange/CALs to keep on a version that receives security updates, the cost of downtime that you have committed to within the business, and weigh up the value of everybody being able to instantly work from home (at least as far as email is concerned) in the event that your office floods or burns down, saving you the cost of a DR plan (for email), because someone else has done that for you.
If none of that stuff matters then that's fine, but just comparing monthly costs doesn't really paint the whole picture. I'd argue that in 2017 it's more important for a small business to have their "stuff" accessible from any internet-connected device than it is to have it working in the office (you get home working for 'free' and can deal with the snow days). Internet connectivity going down at work is going to be a pretty major inconvenience, is being able to email internally still really much of a bonus? Only you/the wider business can make that call.
