The increase in their average home attendance in the last couple of seasons can be almost entirely attributed to Rangers return to the top league - something they are now restricting.
Statistics can be used to prove anything but the Killie average attendances over the last 10 years had been no better than static - indeed, the numbers have dwindled since 1993/94 season which, presumably, was when they returned to the top flight.
Their average home attendances can be found here : http://www.fitbastats.com/kilmarnock/club_records_league_attendance.php
If they take us from 8k to 4K tickets then their numbers this season would be down 8k which, up to this point, would be a reduction of about 500 (8,000 dicvided by 16 home games) meaning their average attendance would be about 6,000 which is no better than season 2010/11.
As someone from Ayrshire who lived in Killie, and whose best friend was the Killie SLO for a number of years but now rarely bothers to attend I can say that their crowds are, and have been, shite since at least the early 80’s when I moved there.
Bowie can be as ambitious as he wants and, as you rightly say, it is his financial risk to take..... but I have significant doubts that this risk is one that will pay off with rewards.