Probably happened before he learned such technique. Such things can't be learned by mere decades even by their standard and such things has a time window limit like it has to be done within minutes of death. .Why couldn't he just revive his tribe?
Beyond what Romisterie said, Blowstone also mentioned how he couldn't FEEL a thing for his tribe's death. Probably thought that reviving them wouldn't do anything, and at most he'd feel the same regardless when some other thing, old age or not, took their lives.Why couldn't he just revive his tribe?