And for all the these writings over many millennia, how many of them contain a scrap of evidence to suggest the existence of a deity? Of course, none! Science won't prove the existence of something that can't be proven, which is why my default position regarding religion and life in general has always been that it's incumbent upon those of whom present a new idea or theory to prove its existence or at least its validity, not the other way around. Unfortunately, Christianity has been around for over 2000 years, so we can hardly question those of whom "presented" Christianity right here and now.
I delved into "Theology and associated fields" only as deeply as I needed to in order to ascertain that none of it provides even a skerrick of evidence to prove that the claims, musings or any other texts contained in any such literature has been proven as fact by adopting scientific methods. Which is why it is my opinion that all that religion does is promote an insular, intolerant and self-righteous mentality. People don't need religion to derive their morality from, nor do they need to devote themselves to a deity fashioned by someone throughout a period in history which just so happened to suit their agenda at the time.
You talk about "billions of lives transformed"; What about the billions of lives lost in the most callous and brutal ways imaginable? All for what? All for a god that we can't even prove exists. If religion helps people live a more fulfilled life, fine. But it doesn't mean that it's correct. Most religious people are peaceful people, but it's not through religion which we derive our core morality from, so those same poeple would be good people with or without the delusion of a false purpose. My biggest issue with religion is the platform it provides for psychopaths with grandiose agendas to carry out mass genocide in the name of a higher being.
Double Ouch..
( But I have to say there would be some on here that would say ...Adelaide city of churches...and your line about insular resides side by side)
By the way ... can someone tell me which God is going to supply our next Flag...thats the OP isn't it.