That is clearly not true imo. In the future if we send out signals in the hope of others responding we would send them out on all known frequencies available to us on which we think it would be possible for them to pick up, akin to "hail on all frequencies" you hear in films and tv. It is also possible that civilizations discover communication methods in a different order than we have or not at all. Also it is daft to think that because we haven't heard out so far that there is no other civilizations out there. Any other planet containing intelligent life may have another planet/moon in its own system that also has life, infact they may have found countless worlds and know of our existence but have found so many that there is no point in contacting us. They could have also been sending out signals in methods we may never discover. Ofcourse there may be nothing out there but that is unlikely in my opinion. The elements that led to life on Earth are everywhere in the cosmos and by all accounts there is a rocky planet around the nearest star to us in the goldilocks zone and in my opinion life wants to happen. i wouldn't even argue about it being fundamental in the universe. Finding bacteria on Mars will pretty much confrm this and i bet we will have that confirmed in 10 years.