For manufacturers it is clearly better for them if their customers are buying their receivers. The companies putting out the multi-protocol systems are new manufacturers without an incentive to keep customers locked in to using legacy products.

Manufacturers are also always pushing for the lowest possible latency, and introducing new proprietary protocols for surface systems. These new protocols usually aren't backwards compatible even within the same brand's range, again to encourage the purchase of the latest and greatest transmitter.

As someone relatively new to air radios, it seems that the protocols stay popular for longer and that there isn't this same continuous push for ultra-low latency, except perhaps with some of the new TBS crossfire gear.

Even an air radio with a multi-protocol setup like the TX16S or J12 doesn't work with every receiver, but certainly a wide selection.

It is also possible to use the TX16s with two modules at once, and has the ability to act as a receiver and transmitter at the same time. For air use this could be used to make a wireless trainer/student setup. I'm interested in trying whether I can bind a surface transmitter to the TX16S in RX mode, then use a second module to transmit to the vehicle. This would allow for some of the more advanced modes and mixing from the air radio to be triggered and used from the surface radio.