The price of season tickets is the main factor as you are paying in advance for watching great football ,excellent results ,entertainment and of course your seat . 
 The  fact that southampton was a premiership club is not enough justice to charge 'a near on premiership price'.why these people who set the prices for tickets think the average punter is a mug who will be blinkered into paying whatever price is set. 
Overprice it and more teams will play to empty seats 
Do they not take into account that there is a global downturn ,plus from a string of bad results from southampton fc .  
Whats to say (HATE to say it)that the team will go on a downward run of form and carry on the way they finished off last season .i am sure that will be firmly in any existing / new season ticket holders minds.  
If they price it right ,then the rest will follow to watch sfc.