1 - No money can be made from it. The best you can do is have a pay site with videos or a pdf e-book or a normal bookstore book, which is minimal in terms of making money off it. Especially when you have somewhere like Thunders which takes donations, but gives all the same info for free. I would go as far as to say Thunders is even better then any of those things because you are learning from people’s experiences and sharing your own. This is invaluable when it’s something that like you said, doesn’t get talked about on TV or other types of media.
2 - It takes alot of hard work and is not an “easy fix” which is what people want in today’s society. Pec implants, butt implants, boob implants, liposuction, these are the things people want. The quick easy fix that they “know” will work. Some people here have posted their penis surgery stories, some have really regretted it and done damage to their unit for no gain. But they were still more willing to try this ahead of doing manual exercises, because it’s seen as quick and easy.
3 - Penis size is taboo to talk about for some people. Even for someone who considers themself large can lie and exaggerate their size, or be scared to talk about it and be shy in the change rooms. If “large cocked” dudes feel this way, how do you think Mr 4 incher feels? Alot of men don’t want to talk about their penis fullstop.
4 - There is a myth that size doesn’t matter. And also that it cannot be enlarged. I don’t know where it started, I don’t know why. This forum breaks the myth. I can imagine that it’s easier for alot of people to accept that nothing can be done and just get on with their lives and accept themselves for who they are. I don’t know about this one to be honest, but it’s what the average person on the street believes. Because it’s the common reply to “I have a small penis what can I do about it”.
Those are the best 4 reasons I can think of. It’s a good question, but also be careful what you wish for. If everyone did PE, the average size would climb and we would need to stretch our dicks even more to become above average. :D