How common is Life in the Universe? Second part

Complex life may be common, but we are only at the beginning of our speculation. Life began in Earth's seas, most probably. And life has to develop on land to create technology. Dolphins are intelligent, but I don't see them building anything, since they haven't manipulatory appendages. Squids and octopuses have, but they couldn't get on land for lack of a skeleton. In fact, only two phyla of the animal kingdom have extensively and efficiently "conquered" the land: arthropods and amniotic chordates, with minor contributions by nemertea, onychophorans, mollusks and annelids. Arthropods major achievement towards intelligence are complex societies like bees, ants, termites. Maybe on a planet a superintelligent colony dominates. Chordates' exploit are we, Homo "Sapisns", Man the Wise. How wise we are we will see later. Getting out of the water is no minor problem for animal life, and, according to some scientists, it requires having a massive moon like that of Earth, that enhances tides and so facilitates the transition from water to land. But many scientists disagree. Another speculate of planets with planetary oceans, where life won't have any land to come to. But if they exist, such planets aren't probably common. Once on land intelligence comes at some point, you should think. But evolution doesn't select for intelligence, or complexity: it selects for whatever comes handy for survival. There were primates in South America and in Africa, and Homo developed only in Africa, South America never experienced the drastic climate changes of East Africa that favored the evolution of the genus Homo. South American Monkeys never saw a reason to leave their trees. And mammals were able to evolve big brains because a meteorite wiped out the dinosaurs. How common is intelligence? We don't know, but it may be not at all inevitable. And moreover, Homo Neanderthalensis was comparably "Intelligent" nearly like us...and they disappeared. Had Neanderthals survived and Sapiens died out, would they have created a technological civilization? We don't know. Homo Sapiens itself didn't became "visible" from space till he invented the radio and television, practically moments ago, on the evolution's time-scale. So, maybe, we are one of the first and few species to arrive at the space communication stage. Homo Sapiens and a handful of species in the whole Galaxy.(And who knows how many in another Galaxies and the entire Universe, but let's consider OUR galaxy) And how Sapiens are we? Major nations of our world accumulated nuclear arsenals which, if deployed, could wipe out civilization many times, causing life to return at bacterial level.Not only that, but we are the only species to massively pollute the water it drinks, the air it breathes, the soils that gives it food. Maybe we've altered the climate at a point to induce dramatic changes. We could go on to describe our "wisdom". Homo "sapiens" indeed! We'll may survive crises and become an enlightened non-warring, non-polluting species. We all hope so. But some intelligent species may have found their way to their Mutually Assured Destruction. So, maybe the nearest intelligent civilization is on the other side of the Galaxy, wondering similar thoughts as we. Who knows?