The Jewish Apocrypha and Pseudepigrapha demonastate that many ancient Jews, besides the Pharisees, believed in an afterlife.
(1) Ir is misguided to consider the rise of rabbinic Judasim after 70 AD as the direct succession Pharisaism. In fact, these ancient rabbis dismiss "the Pharisees" as an extremist Jewish sect.
(2) In Jesus' day there were many Jewish ideologies besides the 3 Jewish sects identified by Josephus--Pharisees, Sadducees, Essences.
(3) Before Jesus' launches His ministry, He was apparently a follower of one one of His relatives, John the Baptist's and John seems to have been an Essene.
(4) In Jesus' day a Jewish man was expected to marry by age 30. Essene monastics were the exception.
(5) The missing years of Jesus' life are hopelessly elusive, but hold the answer to this issue.
Joseph is apparently already dead prior to Jesus' ministry, and as the eldest son, Jesus the woodworker would be expected to care for His widowed mother rather than leave her to join a Jewsh sect.