sony doesn't delete paying customers/ex-paying customers accounts (because they are not retarded like others who do so, like ffxi). even banned accounts stay in the system, on the servers, undeleted.
account keys are unique for each game disk, and you much buy the game to make an account. therefore, you need to have bought 1 eqoa game for every account you intend on making. For this reason, you DO TO want to keep/use your old account. because you don't want to have to buy one from toys r us online for $30, when instead you could use that money for two months of game time (granted it gives you 1 month free, but you're still throwing away $15) (i'll lol petty hard if I have to pack up/see someone pack up an eqoa disk anytime soon).
around the beginning of the month sony completely stopped all console-based account management dealing with money (and possibly all of it period), which means no new accounts can be made on it, nor can any cc/debit cards be used. i don't think game cards can be used either, on the console.
as the above has stated.