I think there's something to this. For gentiles especially, Christianity was more attractive and life-affirming than what they had, as long-suffering subjects of the Roman Empire with little to hope for. Notwithstanding the enduring core messaging, the allure might have shifted over time between some components as quality of life improved (for instance I think the role of 'sin' and 'salvation' qua deliverance from guilt became more significant later for adherents, where earlier on the "afterlife" sells itself when life is shit).