Dale, I applaud you for the most sensible, rational, and carefully argued article on this topic I've read in ages. One minor flaw, however: your assumption that our species will carry on "forever" sending out EM signals. This flaw is replicated in your assumption that any other technological species will likewise persist for significant periods of time. In reality, it's unlikely we'll be around for much longer as we're too stupid to manage the dangers our clever technologies present to us. And an alien species would need to last for potentially hundreds of millions of years in order to be still here by the time we developed our rudimentary technologies. That's a big ask: even the nautilus is a mere 400 million years old; most species come and go in less than one million years.