Quoted from Sinestro:
Why in the world would Farsight pay double to have games in both the Pinball Arcade and the Stern Pinball arcade?
Obviously it's not a great cost issue, so Zen could do both.
I'm not sure I can make it any clearer.
Split resources. Yes, Farsight did it, but it's clear they were splitting resources off TPA that were already pretty thin, it was a pretty buggy product, and was definitely part of why I went from "buy it all" to "only buy if they had something special enough". (Note: I never bought a table in Stern Pinball Arcade.) And their "TPA After Midnight" non-family mode product never went anywhere.
Plus, there would be possible confusion among Zen's customers (why can I buy it in two places, and why would I have to buy it in two places), since they've ALWAYS had just one current engine/front end. And that might also clash with their corporate philosophy regarding content ratings, they may specifically be aiming for the most inclusive possible ESRB rating, which makes a second "uncensored" product pretty much a non-starter just from that.
It's not just money, it's all those other factors going into it. At the end of the day, if you want 'em completely "uncensored"? Either go with Visual Pinball, or complain to Scientific Games about the quality of the licensed product. And I doubt you'd get much traction off the latter, since they'd have reviewed the changes made and signed off on them.