This is why things like SETI (and arecibo for finding ETs) make no sense. I compare it to using a telescope in 1850 to look for https://en.wikipedia.org/wiki/Flag_semaphore in space. The technology we have to send signals today will look completely pathetic to us when we look back on them in 50 years. Why would we expect ETs to use technology that we ourselves will abandon completely in the relative blink of an eye?
-The technology that stems from attempting to answer the problem.
-The unforeseen consequences - i.e. Maybe someday we'll reach technology that can detect signals in a more advanced way than we can currently and, through recording data from the past, have captured a signal years before that technology exists.
-How many people buy into lotteries despite having awful odds? The odds may be bad, but it's non-zero.
the technology doesn't matter, either yesterday, today or tomorrow it will still be electromagnetic waves which is what SETI is analyzing.
Or we might have moved on to laser (highly directional) or something nobody has thought of yet. I promise you we won't be using some kind of nondirectional, multi trillion watt carrier-based radio contraption that we would have to be using to be spotted by something like SETI on alien world.