CPDLC exists and is used. It has its limitations though - it doesn’t provide as much flexibility for pilot replies, pilots don’t always have a free hand to text with (especially in turbulence), and is generally slower and more clumsy than voice so is only suitable for routine, non-time-sensitive messages.

That sounds like a system that was bound to fail, because it was kept limited to a certain range of capabilities.

One can easily imagine a system that broadcasts the weather and clearance, and even aircraft location data close to real-time, and provide great situational awareness to everyone involved.

I don't think it's acceptable to put tens of thousands of people within a crowded airspace and not do everything in our power to keep things organized and secure.