A relative of mine researched our family tree. After 2-3 years she presented it to everyone. Most people weren't really interested for more than 10 minutes, but tried to respect the effort she'd put in to it.
Now we all have less/no future need for an ancestry service.
There are enough people who do it for a hobby and/or religious purposes that it seems like a pretty viable subscription model.
Often novices can't read the writing, and when the records are in another country/region it's easier to pay someone. Also, many records can only be searched this way, the public don't have access.
I tend to subscribe for a few months and then try it again year or two later to see if there's any new gaps I can fill in. There's often new information added periodically, either from a new set of data they've digitized, or user-added content from a distant relative that happened to have some unique information about a common ancestor.
I presume most people are not returning though.