This is a really good question. I've spent thousands of hours developing my methodology, and while it certainly isn't all about an indicator, the pride of place is occupied by a single indicator that is, in my experience, superior to anything I've encountered ... well, anywhere. Would I lease or sell it? Theoretically, no -- for the obvious reasons someone mentioned. But I spent so much time and $$$ developing and refining this sucker, and the resources I've been left with are so modest, that I'll admit I've been tempted to go for a little fast liquidity. But, in the end, I'll probably to continue just quietly trading the sucker. I didn't go this distance just to become a vendor.
Eventually someone will figure out the indicator, and often times, the masses with have it for free. Dealing with the public can be a huge pain in the rump, if you are trading well, why mess with this. Of course like so many vendors who won't post their brokerage statements, it might be their only form of income. Unless the fee per year will pay for a Ferrari, what's the point?