Also, those chipsets come with an SDK, or Software Development Kit.
The receiver manufacturer buys that with a large order of chips.

Some routines are already written, to do the basic functions.
In many cases, the receiver manufacturer doesn't have complete control of the software, relying on pre-written code
That may lead to similar menus , similar shortcomings, and similar bugs in various brands.
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A manufacturer who spends considerable time & money adding functions, doesn't want his work stolen and used on another brand.
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One receiver came to market without motor control.
Apparently the SDK didn't include the feature (or it was expensive).
In the UK, motors are far less popular than in North America.

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