And of course they wouldn't have. Mars was much wetter, with a thicker atmosphere, in the distant past. Life would have evolved as rapidly in an energy-rich, comparatively resource-rich environment such as existed in the Nooachian phase (~4 billion years ago). As Mars lost its magnetic field, then most of its atmosphere, and as vulcanism declined with the loss of internal heat, bacteria could well have adapted slowly to increasingly harsher conditions.
Bacteria live in rocks deep under Earth's surface, under great heat & pressure. Everything we've found so far suggests where there's water, and shelter from hard radiation, there's life. But finding out for sure would be better than speculating.