The big man said October 15th was the last day. I would imagine he was straight-up losing money on coins, and never got the withdrawal process to be more than a check in the mail. Hardly any new players purchased coins, and for most average players (like me) playing a coin game is basically throwing your money away.
I wonder how drastic the changes to coins will be. Micro-transactions for new colors? Will there be a way to earn coins without spending the dough?