Complementary good is a widely accepted economic concept.

Of course, theories and the reality don't always match up.

https://en.wikipedia.org/wiki/Complementary_good

Demand for X goes up when prices for X go down.

First day of Econ 101.

If X consists of two complementary components, A and B, then if the price for either A or B goes down, then the total price for X goes down, demand for X goes up. Which means demand for A and B went up.

Even if the price of only one of A or B went down.

So if the price of A goes down, demand for B goes up.

If software prices go down, then demand for the hardware to run that software on goes up.

It’s a reframing of vertical integration, which does lead to lower prices or higher value assuming reasonable competition. You can also think of it as disintermediation (“cutting out the middleman”).

It would probably be easier to test the other way round: demand for creative software goes up when macs get cheaper.

I mean theoretically that makes sense? If you get more value for something it increases the chance of buying it? But I also have no idea if this statement is true.