If Jws have not got the truth, then -What is the alternative?
You've had great answers here. A life has the purpose you give it. If you want to enrich a publishing company and give false hope to people, that's a pretty poor purpose just so you can die "very happy and contented."
Plus, I deny that most JW's are truly happy. They have this feeling that they are wasting their time, they are made to feel that they never measure up and need to do more. They feel paranoid about accidentally enjoying something "worldly." They miss out on many family joys with their non-JW family.
They indeed miss "the real life." But you don't see that.
Your JW life is alot like living in the Matrix. You can't believe you are living in a made-up fantasy and you cannot see the real world. Wake up, man. You won't wake up because you are afraid you will never get to go back to the Matrix, and the real world with developing your own thoughts/opinions/politics is very scary to you.
Ex-JW's may not know the absolute truth. Neither do you. But I would rather be willing to explore and question than just accept that those guys in NY with a proven track record of delaying and changing the doctrine might actually have anything right.
What other options?
If God and Jesus have a purpose for me, they have my cell number. I don't have to go off and live a life of debauchery, but I can go live my life without a set of imposed rules about blood, beards, birthday cakes, toasting at a celebration, voting, where I should be on Sunday morning and all day Saturday.