Life: an entity which replicates itself with minute errors and whose offspring compete for further replication opportunities. It’s not a perfect definition, some things may fall into this category without being considered alive and others that should be in it may fall out. I’m thinking of viruses and eternal jellyfish as problematic examples. But I digress. The definition should be suitable for discussion purposes.
Gravity is a fundamental force of nature. It’s the most obvious force when you look at the heavens, but also in our day to day lives. This is a bit metaphoric and abstract, but if one were to ask what is the point of the universe, the apparent answer is to create Stellar objects (stars, dwarf stars, black holes, etc). Stars, and planets if NASA estimates are correct, are a common and direct result of gravity. They’re a given in our universe. If we want to say why the universe exists, it makes sense to look at the most common result of its forces; stars.
Terran life appears fragile, Life as defined above isn’t. Replication means when it’s possible to exist, it will become common. It will survive ice ages, meteorites and continental drifts. Life is a given in our universe. Not human life, not conscious life, but life as a concept. So when we explore places mildly hospitable, we will find life.
If we don’t, I’ll have to revise this conjecture. That’s the great thing about scientific philosophy, that’s a fine result.