One obvious response here is that is that season tickets are far too cheap so that people buy them for the big games and don't turn up for lesser matches.
It is clear to be that empty seats are little to do with unsold tickets but 'no shows' by season ticket holders.
Be very careful what you ask for.
Sorry but what Universe are you living in where the £800+ a year I pay for a ST at the top of EL3 be considered cheap?
I often hear about the £325 ST, but aren't they random singles to fill up gaps and so for anyone going to the game with mates not much use. It would be interesting to know how many of the cheaper seats are only used for the bigger games, or as I used to see in and outside the Summerbee bar, being flogged by touts who buy the cheap Season Tickets and only need to sell them for 4-5 big games a season to make their money back.
Around me it's the ST holders who actually show up. There are blocks of seats that City seem to hive off to ticket firms to flog. Some games they are well populated, but many a game there can be multiple blocks of 4-6 tickets sitting there unused.
Another problem we have is that if your ST ticket costs around £40 a game and you can't make a game and place on the ticket exchange, City pop it back on the web, for sale at £70 + and all games, no matter how crap the opposition is are charged at the same price. Until recently, when we are finally seeing Brentford tickets for cheaper prices.
A simpler option would be to ask ST holders to 'opt-in' for each game and if they can't make it, the ticket goes onto the Exchange at a small markup over the ST price.....and taking action against those ST holders who are touting.