True....the simple answer is there isn't that many civilisations around at present using radio and/or communications equipment as primitive as we have. Considering that 75% of all Earth-like planets in this Galaxy are on average 1.8 billion years older than ours, with all things being equal, we're not even out of the stone age, yet
Most of the usual comparisons (them to us being like us to pond slime) are a little demeaning and fanciful, but to be more realistic the comparison is probably more like us trying to communicate with an ant and explaining to it the fundamentals of quantum physics. Or teaching your dog how to build a radio receiver. They would probably find us both amusing and frustrating at the same time because apart from a few basic things, we would have very little in common. You couldn't discuss physics with them, they'd be so far beyond us that their understanding would seem to be nothing more than magic to us (hence the old adage of Clarke's) and our knowledge would be even less than quaint.