IMHO, another company would have either already bought the idea (because they thought they could develop it better), or they will wait to see if it's successful (which will be harder with limited funds). Few companies want to buy unproven "great ideas" because execution is far more important. Also, if the product fails, the cost of buying the company and/or the idea will be much lower. If it's a success it's unlikely you're going to see it run away because the limited funds for operations will limit the potential sales.
Certainly it's worth thinking about, but I would be careful investing based on the notion that a mega brand is going to pony up a lot of cash in the near future.
All MHO.