Obviously everyone's experience is different.
I currently have 3 primary "money" sites and each has a single support person. They have all worked for me (remotely) between 2-5 years, and I talk to them each an average of 1 time a month for about 30 minutes.
I could replicate this 100 times (and be making 8 figures a month) before I got anywhere near being a "full-time manager." Obviously when it got to be more than an hour or two a week I would just hire someone else to do THAT for me too.
Couple of thoughts here ...
1. You can make bank arbitraging offers ... you don't even need your own actual product. Create a relatively low paying lead gen offer that affiliates trip over themselves to promote, and feed those leads into a higher paying offer or sales funnel and boom. There are dozens of ways to slice it without having to actually create your own products.
2. Done right the above can make more in a month than an MFA farm can make in a year.
Different strokes for different folks. I've honestly been tempted to create a ton of MFA sites (with a twist) just to see what might happen, but just can't convince myself it's worth the effort. I'd love someone like you to fill in the missing pieces, maybe we'll meetup at an event one day and argue over a beer.