Developing hardware and software for aerospace is not at all like developing for consumer applications.
In general, every functional unit of code needs to be documented with high and low level requirements, and then a test spec that shows that those requirements have been met.
Open source stacks and so on are out. Operating systems and components such as drivers have to be accredited. Typically they are sourced from specialist companies that specialise in this field, and at many times the cost of a consumer product. (All that documentation and testing costs.)
Over and above this, there are layers of redundancy and safeguards for flight-critical functions - for instance, function A (say, a set of critical sensor indications) will be monitored by a completely separate sub-system, developed by an entirely separate manufacturer and development process. This is because - even with all these standards - errors and bugs still can creep in at the level of requirements gathering, or simply human error.
These are some of the reasons that getting on an aeroplane has been getting safer over many decades, and is generally safer than crossing the road.
With all this in mind, the industry is understandably conservative when it comes to all aspects of technology, from the interface connector to the OS core. It has certain OS's and comms protocols which have stood the test of time, and there is little reason to change them.
The times that I worked on USB, it struck me as one of the most impenetrable and hard to debug stacks I've seen. When it works it is fine, when it doesn't, it's a very specialist job to figure out why. In addition, standard connectors generally wouldn't meet aviation standards (by a country mile) and some aspects of the hardware interface are not differential (as pointed out above).
In essence, USB was developed as a "one size fits all, plug and play" interface that is "good enough" for domestic use. The benefits of standardisation and volume beat the technical shortcomings of the interface (over complexity for many purposes and lack of built in reliability).
The things that make it attractive for (say) a home headset make it absolutely unusable for one used by a pilot.
For the same reasons, you will not see peripherals on an aircraft communicating over BLE, to save cost.