Cool. Here's what has yet to be revealed. Most Fellowships will never take all 4 Perks to level 10 because they won't need to. Assuming a 25K per week XP acquisition rate, which could be high for many Fellowships but I'll use it, it would take roughly 14 months to take one Perk to level 10. For the Spire and Tourney Perks, Fellowships only need to take them to the level of their success. So now, if a FS needs to have a Perk at level 10 to hit their point of success, the next one begins at 475K and adds 50K per level going forward so it's exponentially advancing in XP cost doing just one at a time and doesn't make a whole lot of sense if the focus is on more than one Perk. Taking all four Perks to level 10 using my numbers takes about 8 years.
I think I get what you're saying here: the slower your FS acquires points, the less they actually need the points for things like spire/tourney archive. I don't really understand the math, though. Regardless of the order that you complete them, the total points spent for completing 40/40 perks is 25,000,000. Check out the 'Cumulative Costs' tab on the my link above. A FS getting 25k per week would need 1,000 weeks to complete the perks, or about 19 years.
For what it's worth, I think 25,000 per week is super attainable. There are many FS out there that hit 5 chests & bronze spire every week, and that's 36,000 points before factoring in helping hands. 10 people helping 20 cities 3 times per week where 50% are golden is worth 9,000 points. That's 45,000 total points per week for a fairly inactive group.
45,000 points per week for a year is enough for a FS to get a single perk to Level 9 or all perks to Level 4.