Stern will never make an unlicensed game
cost involved would be according to how hot the property is, which maybe why they do not release a game at the same time a movie comes out
Which is all relative. A title based on hot property will have a larger production run to cater to demand and you can spread the cost of acquisition further (licensing, marketing et al) on a per unit basis. Plus there is the fact that a niche hobby like pinball can piggyback off external marketing for the theme and save outlays there as well - something that Stern does in spades and why they will never make an unlicensed game.
