Exactly. There are absolutely no assurances that you'll find the answer after you die, and that you'll reach heaven or hell if you die naturally or kill yourself. What has so many years of faith given to you? A shitty life that you openly admit to leaving behind? If this is the return when you're LIVING and can do something about it, what assurances do you have other than some book that preachers wrote that you'll receive ANYTHING, let alone good and bad AFTER you die?
Also, books don't prove anything. Anyone can write a book with concepts he or she likes, and provide it to normal people to follow as their goal. If over a period of hundred of years, if his and his followers manage to kill or silence the opposer of that concept, then it's gonna become the new truth, and everyone will follow it because it's what most people are following. There was no science to disprove those "holy books" and the exposure to those books are nothing like what we have today.