Sounds pretty clear to me from that that he would consider selling for millions and millions of dollars or whatever.
(Also, why would the people who wanted to license not counteroffer 2-3 year short term contracts to be renewed on good behavior with the name? Or "$100,000 lump sum + [$20,000 annually for ten years minus however much Toady gets in donations each year]" so that protection against worst case scenario is contingently built in?)
Short term contract wouldn't solve the problem. If a bad game with DF in the title gets made, it won't simply get 'unmade' in 2-3 years, it could linger on the market for years and in the public memory for decades.
As for the lump sum + lifetime monthly cash plan, I'm not sure about the legalities and such, but if he takes such a deal, and the company he takes it from goes bankrupt at some point down the road, he may wind up SOL. Unless I could find some way to get insurance on that monthly income, I wouldn't feel comfortable making a bet that any existing gaming or tech company looking to deal with b12 will outlive Toady and Threetoe.
Lastly, from the perspective of the other side, Paying alot of money for the Dwarf Fortress brand would be a huge gamble. According to the first bit of data I was able to find on the subject,
here, a major, graphical, triple-a video game needs to sell five hundred thousand units to turn a profit. That source is old, but I'm pretty sure if anything game production has gotten more expensive since. This site has about fifty thousand accounts. Not all forum accounts represent a DF diehard who would happily buy anything with the brand plastered on it, and likewise not everybody who loves the has an account here, but I can't imagine that any game would increase sales by an amount of units much greater than the population of this forum simply by slapping the words Dwarf Fortress in front of the title. The amount of sales the b12 comunity would likely bring in, therefore, would only be about a tenth of the sales needed to turn a profit.
Big companies have advertising and accounting departments that are smarter and resourceful than I am. They could likely make a reasonable estimate as to how many sales the DF brand could add to their game, and could easily work out how much money it would take to move that many units through more traditional techniques. For the right price, perhaps somewhere in the neighborhood of the 6 figure deal Toady was approached with, picking up the Dwarf Fortress Brand would be a more cost effective way of gaining sales than traditional adverts, but such a licensing deal would be less cost effective at a higher price point, like say, the minimum amount Toady would take.
Isn't this about what microsoft would make the game into if they bought it?
I think they would have removed most of the major features and dumbed it down to something like Gnomeria. Then have an incredibly basic game left and a bunch of cartoonish art. They wouldn't count on selling a complex game, the people who fund development don't understand what gamers want.
Toady is on record saying that his code is a mess, and that he doesn't ever want to have to work for anybody else. Furthermore I don't think any company with the money to buy DF has the balls to put out a game ASCII. Unless Microsoft is afraid of competing with Toady and specifically want him to halt development, if they want to work with DF they are better served buying a license and starting from scratch than buying Toady out entirely and messing with his code.