Well sure, we can of course ignore the OPs question entirely and make a sort of weird statement about "working as intended" but it really seems like that's for another thread. The OP asked what level people become survivable, and it's about L3, in general.I don't see any problem here at all. Of course some of 'em are gonna die. Don't sweat it.
Most OSR games, if they're doing it right, have very fast char-gen at low levels; which means death doesn't knock a player out of the game for too long. Also, with low-level characters being generally easier to play in OSR, there's nothing at all stopping you from allowing players to run more than one each in the party. That way, when one dies they've still got the other.