I am not sure how I got into this as a hobby, but I got to thinking about it and figured out that there is a big market for the knowledge. For instance I looked around on the web and you can find a lot of very special sites on the internet. There are sites just for specific operating systems like downgradeios8.com and hundreds of sites which are basically about how to jail break your phone. That is where I am sort of making a bit of money on the side. Once you know how to do it, this is not a big job. The big job is learning how to do it and learning how to do it so that you do not end up with a bricked smart phone. Obviously you can turn a smart phone into a brain dead vegetable pretty easily. All you have to do is make one mistake and if it is the wrong mistake then it might not be possible to fix that phone after you do it.
If you think about it, cell phones are where things are heading and I suspect that in the future there will be no one so poor that they do not have one. You will have beggars on the streets taking hand outs via their mobile phones, with paypal or some service like the ones that let you use your phone to pay for whatever you need to buy and so forth. It is not as though many people can do with no phone at this point. Personally I just forget my phone if I am going out to play ball or to go fishing. I do not like having interruptions when I am having fun. In fact I just turn the thing off when I do not want calls.