[dotnet00]

Plus our receivers have gotten more sensitive allowing us to reduce transmit power and a lot of systems use much higher frequencies, which are attenuated more strongly in atmosphere. With another 100-200 years of progress it would probably be pretty hard to pick up a radio signal (that isn't intentionally broadcast) at all from the nearest stars.

[bombcar]

Radio signals sent to space unintentionally are waste - so over time you’d expect them to be reduced or eliminated just because you want to use lower power.