The Pacers know that he's not sticking around, so from their perspective, they're trading away one year of George. Whether he agrees to an extension with a new team or not, the Pacers are still losing exactly one season of George. All teams that are interested in George can bargain from that position, so no team should be giving up assets that are more valuable than a one-year rental.
The minute George said he wasn't staying in Indy, the Pacers lost all bargaining power.