Before agriculture they didn't have this security, and spent most of their time foraging anyways. It is no coincidence that technology evolves much faster after the beginning of agriculture.
If you've ever seen a brown bear...there isn't much you can do if you aren't armed with a gun, and even then....
Of course, the main benefit of agriculture was food security and surplus, allowing a whole bunch of activities not possible before.
At no point was predation a major problem for humans. Again, nutrition and infection would most likely dominate hunter gatherer mortality.
How many remains have we found of mauled humans?
Also as a PSA, playing dead works (better) for brown bears since they aren't so interested in dead things, never try that with a black bear who are more like scavengers. If you saw a bear in he states outside of northern Montana or Alaska (or yellow stone), it was just a black bear.