Afterlife Again

Reading John Williams's novel Stoner (of which more later), I came across this passage, describing his hero William Stoner's reading as a student:
'He spent much of the summer rereading the classical and medieval Latin poets, and especially their poems upon death. He wondered again at the easy, graceful manner in which the Roman lyricists accepted the fact of death, as if the nothingness they faced were a tribute to the richness of the years they had enjoyed; and he marvelled at the bitterness, the terror, the barely concealed hatred he found in some of the later Christian poets of the Latin tradition when they looked to that death which promised, however vaguely, a rich and ecstatic eternity of life, as if that death and promise were a mockery that soured the days of their living.'
Doesn't this perfectly express what's right about the 'pagan' attitude to death and what's wrong about the Christian attitude - the one that leads all the way to Dylan's 'poor immigrant' who 'passionately hates his life and likewise fears his death'? The pagan's relaxed equanimity in the face of personal extinction seems attractive and humane. In fact, the more I learn about evolved late classical paganism, the more attractive it seems, and the more mystifying the takeover of Christianity becomes. The religion of late classical times seems to have been such an easygoing matter, to do with asserting cultural identity rather than searching one's conscience, observing the cult rituals rather than wrestling with the knotty business of belief. With due observance made, a person was free to go about the business of enjoying life, untroubled by thoughts of death and judgment. The supernatural world seemed very present but largely non-threatening and taken for granted, the gods very much like ourselves, apart from their special powers. The afterlife, in as much as there was one, seems to have been a hazy affair that was most unlikely to involve an ordinary person in eternal torments - there was nothing to be feared. Compare this with the ever-present horrors of Christian eschatology and the demands imposed by the Christian belief system on the individual conscience. How did such a joyless and painful world view make headway against the pleasures of pagansim? Perhaps it didn't - perhaps the reason for the phenomenal success of early Christianity was simply the power and beauty of Jesus's actual teachings, before they were distorted into the ugly forms of Christendom as The Church arose. Also, of course, Christendom was very clever at adopting and adapting the externals of paganism (and no doubt brutal in its suppression). I don't know - I'm no historian - but that the comfortable, civilised late pagan world embraced Christianity so quickly and completely (apart from Julian the Apostate's attempted fightback) has long seemed to me a great mystery. It surely can't all be explained by the conversion of Constantine - can it?