Bingos cost quite a bit more than contemporary flipper games. I don't have any price lists handy, but those are all very interesting.

Some quick notes:

There were two main bingo designers, Don Hooker for Bally and Lyndon "Lyn" Durant for United.

Harry Williams designed one for Williams and Ed Krynski designed three for Keeney. I'm not sure who designed Holiday for Keeney, but I don't think it was Krynski.

Don Hooker designed the ingenious circuitry you see and the descending diamond playfield.

Lyn Durant had a different approach to his circuitry. It required many smaller components instead of two larger motors. With the release of Manhattan, United switched to a Bally style setup.

Lots more to the history, but that's a start.

He did - he was scooped up by Gottlieb and designed many many games for them in the metal rail EM era-early solid state.

I don't have a ton of EM slot experience, but I was surprised to see a blatant rip off of the Bally mixer unit in a flasher I worked on from a company called Auto-Bell. They may have had some kind of relationship to Bally, haven't looked that deeply.

Yes, the art for all games was outsourced to just one or two shops. The primary artist, as far as I can tell, on most bingos from Bally and United (until about mid-60s) was George Molentin.