Medieval feedback loops

I've been reading a lot about Medieval history recently. This experiment synthesizes what I've learned so far using feedback loops like this simple example:

graph TD
AW --> |Selective breeding| HS
HS[Horse strength] --> |Can carry more| AW[Armor weight]

As armor weight increased, horses needed to carry more weight and were selectively bred for this purpose. As horses got stronger, they could carry more, and armor got heavier.

This is a simple stock and flow diagram. Armor Weight and Horse Strength are stocks, and the arrows between them are roughly flows.

Early middle ages (800 - 1200)

Feedback loops (early)

graph TD
A[Invading Armies] --> |Need to be repelled| K[Knights]
K --> |Require wealth| F[Lord-Vassal relations]
K[Knights] --> |Carry armor| AW[Armor weight]
AW --> |Selective breeding| HS[Horse strength]
K --> |Require| H[Horses]
HS --> |Can carry more| AW
HS[Horse strength] --> |More power| DH[Draft Horses]
H[Horses] --> |More available| DH
DH --> |Faster than oxen| FY[Farm Yields]
AW[Armor weight] --> |Unidentified horse and rider| H[Heraldry]
TFS[Popularity of Three Field System] --> |Better land use| FY[Farm Yields]
TFS --> |Increased soil fertility| FY
TFS --> |Popular winter crop| O[Oat Yields]
O --> |Horses &#9829 Oats| DH[Draft Horses]
DH --> FY
DH[Draft horses] --> |Used for transport| PM[Peasant mobility]
PM --> |Cut out merchants| CT[Cheap transport]
PM --> |Commute on horseback| TS[Town size]
TS --> |City scale benefits| PP[Peasant prosperity]
CT --> |Less spent on transport| FP[Farm profits]
CT --> NF[Farm distance from rivers]
NF --> |More food production| CC[Carrying capacity]
FP --> PP
CC --> PP
FY[Farm Yields] --> PP

Late middle ages (1200 - 1500)

Feedback loops (late)

graph TD
AW[Armor weight] --> |Bolts could pierce| C[Crossbows]
C --> |Too slow| L[Longbows]
L --> PP[Peasant Prosperity]
C --> |Attempt to prevent puncture| AW
BD[Black Death] --> |Supply of workers decimated| HL[Human Labor Cost]
HL --> |Economics| ML[Mechanical Labor]
ML --> PP[Peasant Prosperity]
HL --> PP
PP[Peasant Prosperity] --> |Uprisings| KW
M[Mercenaries] --> |Need for control| SA
SA[Standing Armies] --> RP[Royal Power]
SA --> |Reduced need for knights| KW
CAN[Cannons] --> |Castles obsolete| KW[Noble Weakness]
L[Longbows] --> |Armor piercing| KW
C[Crossbows] --> |Armor piercing| KW
MUSK[Muskets] --> |Armor piercing| KW
HL[Human Labor Cost] --> |Higher wages| KW
CAN --> |Effective siege weapon| RP
KW --> FD[Feudal decline]