I'm still not bought on early shrines. Let's say you get 4 shrines by turn 50. Game will be over by turn 300 at best. So that's 250 * 4 faith per turn. In other words, that's just ONE great person. You are essentially trading 4 * 40 hammers (about 8 turns of production early on) to get that one great person at the very end of the game.
Meanwhile, you could have gotten 2 workers, 2 libraries, or 3 granaries, which in turn accelerate growth/science and snowball, whereas your faith per turn is flat at does not snowball anywhere.
Alleria, there's nothing wrong with your math, but you are applying it in a linear fashion. In a vacuum, you'd be correct, but you are ignoring the other half of opportunity cost.
-IF you build shrines early, you are likely to get earlier pantheon/religiion AND you will enhance/spread much earlier.
-IF you build shrines early, you are more likely to build temples and therefore Grand Temple.
-IF you build shrines, temples, GT AND have a good pantheon, you've got a shot at CS requests.
-IF you build shrines, you are more likely to grab a few tenets in Piety, which can double their value (or more).
-IF you build shrines early, and get some sort of religious building, you are much more likely to pay 200 or 300 faith for those buildings than 400+. That's a huge savings.
The value of shrines cannot be measured in a vacuum and it differs every game (depending on who your neighbors are mostly, but also on your strategy that game).
Given that shrines are so cheap and available very early, I'm fine delaying something like NC by 5 turns in most games. By the time you have your 2nd and 3rd expo up, you'll know if you are going to have a decent religion or not. At the very least, build one in the capital as the pantheon boost almost always pays for the hammers even if you are going to have a weak or no religion.
There are very few starts/civs where you know ignoring religion is the right idea immediately. And a strong religion, in the right hands, can make a huge difference (In a recent DCL, I pulled out a SV late mainly because I could afford one last GS. In that game, I never spread my religion, but the extra faith all game is the only reason I won).
Just my 2 cents.