For extreme cheapskates, would rotating your rotors front to back make any sense (assuming same size discs)?
Since you mention "extreme cheapskates", I assume you're asking if it would save any money. In the long term, it saves nothing. It might help to think in terms of an analogy. Suppose you have two machines that fill soda bottles (imagine that putting soda into a bottle is putting wear onto a brake rotor). You have a machine that pours two litres per second and a machine that pours one litre per second. Assuming that you move bottles instantaneously between machines, you don't get to fill more (or fewer) bottles per minute by moving part-filled bottles from one machine to another, because your machines still only pour three litres per second between them. So, in any given minute, you fill 90 2-litre bottles, regardless of whether you fill each bottle entirely on one machine or if you part-fill a bottle one one machine and top it off on the other, or transfer them back and forth even more times.
Note, though, that this argument relies on long-term averaging. Since brake rotors last a long time, I guess you're not going to have many replacement rotors over the lifetime of any particular bike. For example (completely making up the numbers, here), suppose that a front rotor lasts five years and a back rotor lasts seven years. If you swap the rotors at the right point, you won't need to replace either rotor in the first six years. Suppose you were going to replace the whole bike anyway after six years: swapping rotors at the right time means you didn't need to buy any replacement rotors; not swapping them means you needed to buy one new rotor.
But Criggie's comment suggests that you're unlikely to need to replace rotors at all, so all of this becomes moot.