> I'm sure our own broadcasts fizzle out into noise before they even reach the Proxima system.

Consider that we've only had a few decades of analog transmissions that are receivable from space, and we've rapidly transitioned to small-range high density terrestrial infrastructure with not just QAM but encryption on top of QAM, in addition to very narrow-beam communications with our local(ish) space vehicles out of necessity to make our range reach our heliopause let alone the nearest stars…

The vastness of space and the speed of light teaches us that distances in time are supremely relevant to the Fermi paradox - if a nearby alien civilisation was merely a century or two behind us (basically nothing in the scale of the universe), they'd never know that they missed our golden years of blasting everything into the sky.

I've been to the Honeysuckle creek radio telescope before, and I asked them if any foreign object ever went through their telescopes' aperture - and (with some reluctance) they told me they'd vaporized a bird once, and even that sort of transmission power would be abysmally difficult to detect at stellar distances even if that sort of transmission had another star perfectly behind the spacecraft they were communicating with at the time.