Licenced themes sort of guarantee sales but its still aimed at the operator market whereas most pinballs these days end up in private collections.
If out and about and you see the latest movie set up as a pinball you are more likely to go and chuck a coin in... well thats the theory anyway. STERN have their own recipe for all this and the basic layouts of artwork etc are repeated over and over which to a pinhead lacks imagination because we have seen it all before.. many times!
Riding the wave of a movie or TV programme has really been the norm since TAF and TZ.. but the sales are yet to be repeated.
Problem with many movie themed games is that they can start to look a bit cheesy after a short amount of time.. im not a fan of big commercial American films, i find them so tedious and so games like Twister have never and will never have any appeal for me.

The cost of a licence wouldnt be cheap but it no doubt is cheaper than having to create artwork... quick snapshot of the actors and you have the PF centre.... movie grab and you have the sling plastics etc... group this together and you have the translite... basic simple stuff.
Aliens, monsters, space, fantasy have nearly always sold well as non themed games... it wouldnt be too hard to come up with some artwork based on these themes and its longevity if done well will be cemented in history.. a zombie pin aimed at adults would be a killer of a game if it was void of any actors faces on it. Would like to see the same team that made Circus Voltaire do this kind of theme. I reckon they could make another timeless piece just like CV