Not true, Agatha. The games you buy are accessible forever. I cancelled for a while and had deleted a few games I had bought. I changed my mind about the deletions and was able to sign in to my (cancelled) account and re-download them!
I rejoined a couple of months ago. All but one of the games performed beautifully. One game stopped loading. Customer service was quick to respond, which is refreshing these days. The rep emailed me links for updating my drivers and when that didn't work, she promptly gave me a coupon for full cost of a new game.
I love Pogo, too, but Big Fish games can't be compared to Club Pogo.
If you feel like buying only one game, you can just buy it for $9.99. (down from 19.99.) Or you can get games for less if you commit a minimum number of games.