I agree not every website needs high availability... but I wouldn't bet my $600k/yr business on a single VM's availability and reliability. One day, his server is going to die and be replaced by his host, or his disks will need replacing or a RAID array will fry...
It seems like his business could at least afford an HA setup on a cloud provider. Moving to any hosted db with backups, updates and redundancy could be worth it.
As for HA failing, it's still less likely than not-HA failing.
Also an HA setup allows for maintenance and upgrades without downtime, which is way better than the very common "we don't upgrade if it's working, because it could break".