They would have to rewrite entirely their software. There had been some attemps to use these Qualcomm processors in cameras (the Yi M1 for example) and the result was terrible, the autofocus specially.
The much larger sensors on a dedicated camera take longer to read out / have physical shutters / are very power hungry, so doing bursts is just a worse tradeoff on a dedicated camera than on a phone.
Also, the camera market is much smaller than the phone market. Also, most camera companies are Japanese and Japanese companies are generally speaking not as good at software as they could be. (Though this is getting less true.)