Will Wright was very vocal about considering the 1990s-era Sim series to be "toys" and not "games".
Interesting. It seems apt -- a toy is something you fiddle with without specific rules... but I'm not sure the distinction's that important, things can be both. What's missing from simulation games isn't so much winning or losing conditions I think -- it may not stop you and say "game over" but you can certainly smash the setting into a state you can't recover from. Or rules; you're free to play as badly as you want in almost any game, you just won't win. All that's missing is a rigid storyline. So I'd still say Sim City and Dwarf Fortress are games. And "toys".
I think he's arguing from a definition point.
A toy is something you play game with.
A game is just something you play.
For example, a game have a set rule (like chess, you have 1 objective, a set of unchanging rules, etc).
A toy can have almost infinitely many objectives (you can't "win" playing a toy). So for example of SimCity, it doesn't have a well defined objective, instead, you choose your own (most population, most dense, lowest traffic congestion, most efficient, least polluting, most polluting, highest traffic count, etc).
So by this standard, Dwarf Fortress is more like a toy (a REALLY complicated toy).