In terms of of non-water based life being "unlikely", I think it's a bit of a fallacy to make inferences on the likelihood of a possibility that we have so little understanding of.
True, we've only seen water-based life firsthand, but our "sample" of reality is so infinitesimally minute relative to the whole that we cannot properly use that as a basis to make assertions about what the overall proportional makeup of types of life might be. Doing so is pure speculation.
It would be sort of like randomly picking up one tiny pebble at random from anywhere on the earth, identifying its elements, and then concluding that it's "unlikely" any other non-identified elements exist on the entire planet because they aren't in that particular pebble.
True, we've only seen water-based life firsthand, but our "sample" of reality is so infinitesimally minute relative to the whole that we cannot properly use that as a basis to make assertions about what the overall proportional makeup of types of life might be. Doing so is pure speculation.
It would be sort of like randomly picking up one tiny pebble at random from anywhere on the earth, identifying its elements, and then concluding that it's "unlikely" any other non-identified elements exist on the entire planet because they aren't in that particular pebble.