There really is greater happiness in giving then receiving. So if they lived a meager poor life, thinking it was all giving, and in their heart it was, they will be happy. If they wake up on TTATT, then the giving may seem like it was waste and a lie, then they may despise all the wasted time or if the sacrifices were for nothing. Giving to the poor and needy though is never wasted.
It's very hard for those of us who do believe in God and whether whole bible or not in if should wake one up or let them be happy how they are. It will come down to how God will judge......will it be looking into their hearts (they all truly feel it's right), in which case waking up is risky if they lose faith in everything, or since the scriptures speak of judging others and such, will he see it as hypocrisy and hold the judgements they had on others on themselves. If he looks into hearts, many may be excused. Or will he see the devotion to the men as idolatry, no excusing for ignoring the bible, and hypocrisy for judging others on the truth when they didn't have it. (in which case waking up is their only chance).