I've listened to liveatc.net, and then took a flight in an Extra 330LS stunt plane and got to listen to ATC from an actual headset...

...and I can't understand hardly a word they say. Even having a slight idea of the phraseology from countless hours in MSFS and watching VATSIM streams on Twitch, when it comes to the real thing, they talk so fast and there's so much static that it blows my mind that anybody can understand them at all.

Commercial rated pilot here. It's definitely a bit of a learned skill, but it doesn't honestly take that long to learn, and it works better than any other alternative might. The most important thing is for everyone in the system to be willing to speak up if they don't clearly understand what's been said to them. "Say again slower" is a perfectly acceptable response, and is a required one of a pilot or controller who did not understand what was said.

Controller cadence is a bit geographical - the busier the airspace the faster the tempo, and the more important it is to speak up.

AM simplex radio works amazingly well overall for this purpose, and none of the potential technology that could replace it would be as safe or reliable..

As former aviator working in tech it, amuses me how periodically on this site, someone learns how the aviation community is flying around using GPS and simple UHF/VHF radios and NAVAIDs, immediately goes into a tizzy about how unsecure and hackable it allegedly is, and then goes round the bend about things like encrypted comms and starts answering a question no one asked.

Like, sure, in the military there's the ability to do various and sundry things to secure your comms and navigation which are not worth discussing here. But in the civilian world, there's largely no reason to go to the trouble and expense.