First of all, in the OP "kill power" and "staying power" are multiplied. I don't know why.
Let's say every time a fighter goes up a level, he gains an apple, and orange, and a peach. A first level fighter has one apple, one orange, and one peach. A 3rd level fighter has three times as much wealth (3 of each fruit). That's linear. If someone with 20 hitpoints and +2 to hit is a match for someone with 30 hitpoints and +1 to hit, then AFAICT things work like they do for fruit.
Now I don't think that fighting power isn't exponential in 3E. I'm just saying that I don't see how the OP proves it one way or another. I think the OP makes some sensible predictions, but AFAICT it assumes the thing that it attempts to prove.
And also, people say that quadratics increase faster than linear, and that's not exactly true (or completely stated) and can cause you to reach incorrect conclusions. A slope of a parabola increases as x goes to infinity, but it doesn't mean that within a given range* (say levels 1 to 30) that a parabola would ever outstrip a linear. For example y=9200x is greater over the given range than y=1/4x^2 even though the first is a linear function.
Thus, I think there are too many variables here that are undefined and too many assumptions that are being made by people trying to use these formulas. With some tweaking, I think you could get a polynomial function that approximated a linear function over the numbers of interest (1 to 30). Basically, I don't think that the math is doing much more than putting a gloss over things people already believe to be true.
*(edit: er, domain - you get the idea, don't get all exponential on me)
Let's say every time a fighter goes up a level, he gains an apple, and orange, and a peach. A first level fighter has one apple, one orange, and one peach. A 3rd level fighter has three times as much wealth (3 of each fruit). That's linear. If someone with 20 hitpoints and +2 to hit is a match for someone with 30 hitpoints and +1 to hit, then AFAICT things work like they do for fruit.
Now I don't think that fighting power isn't exponential in 3E. I'm just saying that I don't see how the OP proves it one way or another. I think the OP makes some sensible predictions, but AFAICT it assumes the thing that it attempts to prove.
And also, people say that quadratics increase faster than linear, and that's not exactly true (or completely stated) and can cause you to reach incorrect conclusions. A slope of a parabola increases as x goes to infinity, but it doesn't mean that within a given range* (say levels 1 to 30) that a parabola would ever outstrip a linear. For example y=9200x is greater over the given range than y=1/4x^2 even though the first is a linear function.
Thus, I think there are too many variables here that are undefined and too many assumptions that are being made by people trying to use these formulas. With some tweaking, I think you could get a polynomial function that approximated a linear function over the numbers of interest (1 to 30). Basically, I don't think that the math is doing much more than putting a gloss over things people already believe to be true.
*(edit: er, domain - you get the idea, don't get all exponential on me)