You tell me we can't compare exceptions, and then use an exception (5 pop Capital before Pantheon) as your base of comparison. You're likely to get your Pantheon at 3 or 4 pop if you make Religion a priority. If you don't, then guess what? You're at a big disadvantage for getting a religion! 3 pop is 16 faith, which is 4% of a Prophet on Standard, and 2.67% on Epic where the test was done. 4 pop is 24 faith, for 6% on Standard and 4% on Epic. Testing a flat-faith-per-population on Epic put me at a disadvantage using the Pantheon. Also, the test was on Immortal, I didn't' prioritize Shrines, and I got FIRST religion. Had I been a different civ and prioritized shrines, I probably would have done better.
On Shrines - 65 hammers. Capital produces 4 hammers without terrain. Hill makes it 5, one decent tile makes it 6 or 7. You have your first Shrine on turn 9 or 10, assuming no Forest settle. Pantheon on Turn 40, assuming no other Faith bonuses. You're getting 60 Faith towards your Prophet from your first shrine alone.
Research a Luxury tech, then Pottery, build Settlers after Shrine - Scout - Monument, at 4 pop. 13 production towards Settlers is not uncommon (this example start I'm playing did it with two Plains Truffles and 2 Plains), giving you your first Settler at Turn 34, second at 42. 3 cities settled at turn 45. Shrine 2 up on Turn 59 (two forests, bought a plains forest truffle, settled on grassland river), Shrine 3 up on Turn 62 (Settled on Hill River, bought a Grassland Cattle, had a Grassland Forest Truffle and a Grassland Horse).
Total faith from Shrines by Turn 90: 119. In my experience, you have a good 10 to 16 turns past Turn 90 before all the religions are founded (extrapolating from Epic to Standard at 2/3's of 150 to 160) granting another 30 to 48 faith from Shrines. If you get any sort of real help towards this goal, you can do it faster (18 production in the capital while building settlers is totally doable with Tradition, much faster expansion Shrine production is standard with Progress). So, we're looking at needing 300 faith from non-Shrine sources for FIRST religion, and <250 for ANY religion, on standard. You have 50 turns to get this for first, so average 6 faith per turn from pantheon, and 65 turns for any, so average 4 per turn, ignoring external sources (ruins, religious city states, Tradition). If you take Tradition, you can get your 3rd policy turn 60 to 70 (Musician, 6 free Culture) That's another 60 to 90 faith towards 1st, or 90 to 135 faith towards any.
Founding a world religion is not something that should 'just happen' without investing into it. Building a Shrine first in three cities with average spots is not asking a lot of investment, and has a good shot at getting you 1st or 2nd. Your Pantheon can't do most of the work and get you a good religion. It can do half the work and get you 1st pick, or 3/4s of the work and maybe miss it. You need to make up the other half some other way.