I was thinking of the term peak corny....since the beverage manufacturers stopped using them, yes, we are past peak....but our homebrewer needs are small, so even if every homebrewer in America needs an average of 10 corny's, there are probably enough corny kegs to go around. Same if the brewers stop using stainless kegs or even glass bottles.
AHA membership is about what, 30,000, and let's say only 1/3 of homebrewers belong to the AHA (we know it is all the good ones, right?). 100,000 brewers. If we all had 10 kegs on average (which is a higher number than probably actual), the total demand is 750,000, and if we need to replace 1% per year (which seems high, too) , that is only an additional 7,500 per year. Someday, we run out of reconditioned kegs....but I am not sure there is a real shortage now. I don't know what the cost should be, but it shouldn't be spiking due to shortage, but maybe more likely due to increased demand for stainless steel....and every time I see someone mention that they are becoming scarce, that time is not now and it drives me nuts.
Current prices seem to be $40-$50 retail, or $20-$35 resale or wholesale. Is that reasonable? I don't know.