That's it exactly. In the days when the gas utility made its profit on selling and delivering natural gas, there was a serious incentive to buy the product at the lowest price possible. Consumers Gas in Toronto had 20 year contracts for supply, and when they didn't sell it all (it was a "must take" or "pay" contract), they stored the surplus in underground storage for those bad days in winter when they needed extra.

Now that there is no money in selling natural gas, they don't really want to handle it, so they are not going to contract for long terms, especially when customers can quit and go to a different gas broker for his supply. If your sales are not stable, you arn't going to commit to purchase large amounts of gas.
They are actually forcing customers over to the brokers, who may or may not give a better price, it's all in the contract, be sure you read it before signing.