Things you can run
The arguments elsewhere on this site are easier to feel than to read. This is where you can move the rule and watch the behaviour change.
Amplification and restraint
One quantity, growing in proportion to itself. One stabiliser that engages once a threshold is crossed. Some noise for everything the model leaves out.
That is the smallest system with both forces in it, and it is enough to produce runaway growth, collapse, oscillation and stability — depending only on the relationship between the two numbers.
Growth and restraint are in proportion. The system settles at a level it can hold — which is the interesting case, because nothing dramatic happens and it is easy to mistake for luck.
Try this: set stabilisation to zero and watch what any amount of amplification does. Then raise the threshold — the system survives longer and fails harder. Then set stabilisation high and amplification low, and watch a system get destroyed by its own safety mechanism — the restraint costs more than the growth was worth.
This is a toy, and it is not a claim about any real system. It is a model small enough to be understood completely, which is the only kind worth reasoning from. The related thinking is in Thresholds and feedback.