I am dabbling in a couple of niches...
...and I'm completely lost. On why the buyers buy.
The niches are online guitar lessons and woodworking plans.
Obviously "why would anyone pay for these?!" right. But SOME people do. Enough to generate low 7 figures per year for these companies.
Why would someone would pay for a single plan? They want to build that exact thing. It makes sense. Or why someone would buy a single lesson or a course on a specific topic. Because they have that specific desire or need. One can hone in on the painpoints related to that and "turn the knife". But why would someone buy 16,000 woodworking plans? Why would someone join a membership site for 1000's of guitar lessons?
I understand a little about the demographics of these 2 groups. Older men who have the time and money to relive their youth for guitar. For woodworking it's the same but more about accomplishment and stress relief. I know why they are into their given hobbies. But I just don't know what angles to use to find the buyers of these things in the larger market.
I have read Cashvertising, Scientific advertising, Breakthrough advertising, and many other infamous copywriting books. I've even read some Carl Jung books based on a suggestion from Ronnie Sandlin. Everything makes sense when dealing with specific offers. But for these broad "all-in-one" offers I don't get it. What am I missing?
The BEST way to see into the minds of your audience, would be to go where they hang out.
Browse niche forums. Join relevant FB groups. Read niche blogs - even sign up to mailing lists to see how they're being marketed to.
Identify pain and pleasure points. Learn their jargon.
Then craft all this into your advertising.
Amy
Guess what, my son is just learning how to play a guitar and I already bough 2 smartphone apps for him, then membership to one site with lessons and now he showed me another one that he'd like to get access to. So you could say, he already "converted" 4 times 
So let me sum up what made him wanna get those and you can use that in angles 
1. His main points: He doesnt want to take regular lessons, because they teach a lot of theory, progress slowly, don't teach just what he wants, and he'd have to actually go and attend the lessons somewhere, at fixed hours.
The possible angles from this: learn guitar faster, form the comfort of your home, skip boring theory and learn the songs you want to, not the ones your teacher wants you to play.
2. He found tons of stuff for free on youtube and countless websites... the problem is the info is all over the place, unorganized, it's often just partial content that upsells some paid course. This made him get lost and overwhelmed by all the info out there and he had problems following it, the promo lessons made him believe there is better stuff in the members areas of paid course.
Possible angles: Don't follow multiple sources and get lost or confused, follow a well organized guide/course by just one person. Show samples and clearly communicate the added value for paying members. The emphasis should be on "all content in one place, organized, easy to understand and with no limits".
3. As a kid, he can hardly stay focused for too long. One day he learns a song from Nirvana, the next one he jumps on Red Hot Chili Peppers, then Metallica ...
Angles: He got sold by the sheer amount of songs/lessons available in some of the courses, the more the better, because he knew if he lost interest in one, there would be tons of other to choose from. So large variety of songs is a plus, focus on that.
4. He loved the idea of a free trial... he literally bugged me till I gave in, after all, it's for free right? Of course I forgot about the trial, since I wasn't the one using it and rebilled for 2 times for 1 of the apps.
Angles: emphasize the trial if there is any, emphasize the immense value of FREE ... seems to work fine with certain audience. I was also more likely to get him access to an app with trial, compared to those that wanted a payment upfront.
5. Reviews : he slowly learned there were reviews out there for everything, but he's not yet able to judge how real the reviews are. So I'm sure even fake or half-assed reviews could work well.
Hope I gave you some food for thought, kids are great inspiration 