They might use ICs that are specially made for them but you can't buy the ICs.
Of course it is, but is it worth it?,
THose radios in particular run on protected frequencies so you can't legally DIY one.
Some receivers have pic micros in them for dsp
The code may be protected........
I guess you are pointing out that the cost of reverse engineering would be exorbitant.
It will be impossible to even think of manufacturing the product at $35. The only way to solve this problem is that I manufacture the radio inhouse.
If you are planning on doing this for buisness, then the ethical thing to do would be to design your own. If you get together with a manufacturer, which you will have to do to mass produce the component boards, they may be able to help you. Even if you don't care about copying a design, you will work harder to replicate their chip than you would have to to make your own design.
On a side note, I have been working on learning how to make RCs and as I make the project and learn I am developing a tutorial walk through of it at the same time, when its done and refined I will make it availible in the projects section here and you are free to use it.