Some evidence seems to suggest that alkaloid concentrations peak in winter, when it is cold

Keep in mind that this is including plants in the Andes, that have cold wet winters

Do alkaloids increase in amount as plants age?

It seems to be true to a degree, but there seems to be responsive alkaloids production, seasonal variation and nutritional factors all relating to this.

What I mean to question is the idea that as a plant ages, that it gets more potent, there might be a maximum potency determined by various factors and once the plant reaches this, it may not increase alkaloid content above it.

Lots of people seem to have experience relating that desiccated or dried plants appear more potent, but has anyone tested this?

If you took two identical cuttings of the same plant, that were the same age etc, and then extracted one of them as is, and then dried the other out and then extracted that, would the dry one be more potent?

In general I agree with Mew, but there are a lot of untested and unanswered questions regarding this matter and experimentation is needed.