Succession is hard for businesses with a majority "intangible" value. Think private practice doctors: your patients are with you because they like you as a doctor, so the "value" of your business is tied directly to your continued involvement.

Family businesses have traditionally gotten around this by having their children involved for 10+ years prior to taking over. That way, you slowly transfer your "social capital" to the new owner (in this case your kid). This is understandably harder to manage with a stranger, because you can't transfer the value before they buy it, but they won't buy it if they can't guarantee you'll help them transfer the value.