I find the notion that respec costs holds inflation in check absolutely laughable.
The cost is high enough to be prohibitive. Thus less gold is almost certainly spent on it than would be the case with a lower cost. What the high cost leads to is a situation where the vast majority simply avoids it.
There isnt a lack of arguments for keeping the cost high. That one enjoys that players are speclocked for rp reasons or simply that any deviation from vanilla is on principle bad. Those are real reasons the economic argument is silly.