> ammonia-based life form at our stage of exploration is probably gonna scoff at the idea of scaldingly hot liquid water
Ammonia-based life exists within water habitable zones; Mars is within our Sun’s conservative habitable zone [1]. (Also, “ammonia boils at 98°C instead of –33°C” at “60 atm, for example, which is below the pressures available on Jupiter or Venus,” meaning “ammonia-based life need not necessarily be low-temperature” [2].)
One reason to suspect ammonia-based life is rarer than carbon-based life is the universe contains a fifth of the nitrogen that it does carbon [3]. (This is why silicon-based life is also almost written off.)