Runescape? You mean that game everyone used to play years ago?
The game is still alive mate. There are constant 40-50k players on. Although not as much as there used to be because the bots are now gone, that is still a large number.
But as far as Jagex accepting bitcoins, that would the best thing ever. I can see some player who have not played in a while jumping on just because they can get a month of membership easily by bitcoins. Someone really should suggest this to Jagex.