I agree. Above I mention that neurons have finite resources so synaptic strength is essentially zero-sum. When a new set of synapses becomes strengthened, it implies that all the other synapses must be weakened by some amount.
Here is a nice animation of signal propagation in biological neural nets:
To simulate the dynamics of synaptic strength I created 3D mesh of a dendrite segment with several synapses...
Then I simulate the diffusion of AMPA receptors on the surface (the number of AMPAR in a synapse is proportional to its strength)...
I don't have animations of this process but you can imagine what happens when one synapse holds onto receptors longer than the others (has a reduced particle diffusion rate), when there are a finite number of receptors