Teleop and monitoring are systems that we've built ourselves and are pretty happy with. Since we use MuJoCo for simulation/visualization and some kinematics subroutines, to visualize, I just keep the MuJoCo GL context open after rendering and then throw all of our sensor data into it - it's very performant and low latency!
We've since introduced a message-bus layer that makes it possible to do it all over the internet etc, but adds the associated serialization and transport latency.
For a robotics company, their code is the "secret sauce" that makes their company valuable. It wouldn't make sense to open-source it all and let their competitors do the same thing without having had to spend so much money and time developing it.
Open source works great for shared code that isn't part of the "value added" by a company. So for a modern robotics company, it makes a lot more sense to use Linux for instance rather than rolling their own proprietary OS. And to use an open-source compiler for building the code. They're in the business of providing solutions using robotics, not selling operating systems and compilers, just like countless other companies build their products on top of these infrastructural tools, and sometimes contribute bug fixes and improvements back. But the code that actually makes the robot work (vision, motion planning, etc.) is what they spent most of their funding building, so giving it away makes no business sense.
Basically, you're complaining about all companies having trade secrets, and ultimately, you're complaining that competition exists instead of just having a single company having a monopoly over a whole market.
We've since introduced a message-bus layer that makes it possible to do it all over the internet etc, but adds the associated serialization and transport latency.