What would human life expectancy be if we lived in the wild?

One way to think about this is to look at what lifespan was when we did live in the wild. Until settled town-dwelling began (around 700BC in Europe), adult life expectancy was around 29 years. This is calculated from the age distribution of burials excavated, so probably excludes all those who died near birth - probably a very high number. Things didn't get much better for the next thousand years either - average life expectancy in the Roman Empire was probably about 35 and if you made 50 you were old.

If you mean how long would we live in the wild today with current medical technology, then I suspect it would reduce old age somewhat, giving a life expectancy of around 65.