They address this by having the video player stop buffering more than 30 seconds ahead. It's also less compute resources for the servers to send all the bytes

They address this by having the video player stop buffering more than 30 seconds ahead. It's also less compute resources for the servers to send all the bytes for the next 30 seconds to a client at max speed, let the client disconnect and wait 3-5 seconds, then give them the next 3-5 seconds immediately when it's requested. If they only let you download video at a rate slightly faster than video playback rate than all clients would have a constantly open connection downloading video which would tie up more resources.