Except that is all almost meaningless when talking about cultures with dozens of provinces.
In the end 95% of the development work is done by AI counts and dukes. The only meaningful thing the player can do is beeline the techs that raise the soft cap.
The biggest culture in the game is Greek (867) with 83 countys.
if you're improving 1 province directly + 8 profinces indirectly you're speeding The whole Culture Development by 11%.
its gonna be flashy and instant? No
But its gonna add up in a game that have close to 600 years of gameplay.
Byzantines have a province that border 7 others, most provinces in the world also border 4-6 provinces.
Also +0.1 dev/level takes 83 years to improve a province by 1 development, so... spread is pretty weak.
You're really underestimating how this adds up. Its a huge snowball effect once you get that ball rolling.
getting a province from 5 to 10 dev with a lv10 Stewart is gonna take.
23 years. (So your 16 year character is now at 39).
if you use lifepath + Planned cultivation it takes only
14 years.
And lets be honest, a lv10 stewart is a bad one. Most will have a constant 15-20 stewart unless a temporary setback happens.
So its even quicker.
Now lets calculate the other provinces.
lets say there are
5 provinces bordering that province.
to go to lv6 they're gonna take around 26 years ( +0.1 for 4.1 years, +0.2 for 4.3 years +0.3 for 4.6 years +0.4 for 4.9 years +0.5 for close to 8 years).
lv 6 to 7 = (constant +0.4/month) = 20 years (17 years with +15% lifepath ) .
lv7 to 8 = (Constant +0.3/month) = 27 years (22 years with +15%)
lv8 to 9 = (constnat +0.2/month) = 41 years (34 years with +15%)
lv9 to 10 = (constant 0.1/month) = 83 years (70 years with +15%)
Remember all the bonus above will spread to 5 provinces at same time. Instead of just 1.
Basically in the lifetime of a single ruler i improved 6 provinces by 5 levels.
But will not stop there.
Those 5 provinces also border 10-20 other provinces.
They're gonna improve too. A little slower but its gonna happen.
Bigger you make the difference beetween province A and its neighboors faster this effect is gonna happen.
Not gonna say +0.1 research/speed is gonna change the world.
but again, it does add up.
but true the fastest way to increase research earlygame is to improve fascination. Easy as the first lv of scholar already gives +35% and events that give learning are plentiful. So there is little excuse to not have close to 75%+ fascination. (basically learning 10 + that lv).
Development is a longterm plan.