The reason is because it's a hard problem that requires a lot of work to solve. Dynamically change video quality to fit in the bandwidth, work correctly with a

The reason is because it's a hard problem that requires a lot of work to solve. Dynamically change video quality to fit in the bandwidth, work correctly with a hundred different types of webcam, do echo cancellation, and wrap the whole thing up with a simple UI. Echo cancellation by itself is a hard problem.