That's precisely the problem; they continue to support the game, in the state that it's in. Honestly, an appropriate move would be for them to officially discontinue support for the game altogether (even if that means not having a new IP to replace it with). This means turning off their official servers, and removing the ability to buy/sell inventory items on the Steam Marketplace.

Right now, Valve allows people to sell items for real money (which they take a cut from) in a game that is overrun by bots. They need to either fix the bot problem, or stop taking people's money.