Sean O'Keeffe, speaking in his Kerry FC capacity rather than as KDL chairman, states that limited capacity was the reasoning behind the main stand pricing (paywall):
https://www.independent.ie/regionals...-42198675.html
The flaw with that argument, however, is that 500 seats at "matching" rates would seem to have had a realistic prospect of selling out, given the interest in the licence announcement, whereas now they'll be doing well to sell half by February, making them more dependent on match-day receipts.