Nah - the insulation material costs ~ $0.80/liter, whereas aluminium conductor costs $6.50/liter.

If you can have the conductor 1mm^2 thinner (capable of carrying less current for the same heat production) and the insulation 1mm^2 thicker (capable of handling a higher voltage) and transfer the same power, then you'd save money.

It only works up to a certain limit obviously - the relationship is non-linear and there is an optimal point.

The actual tradeoff involves a lot more modelling, because you need to consider all kinds of other factors, not just the costs of the conductor and insulator.