Pinball itself is nostalgic.
The Batman TV series is certainly nostalgic.

The combination made what was for me a blind faith buy.

Batman 66 would be a bust as a PS4 game because that's not the target demographic. There is new blood coming into pinball of course, but it's nothing compared to those of us who grew up when pinball was everywhere. If you didn't play pinball on location in the early 90's or before, you aren't the market Stern is catering to.

That will eventually change if new pinball manufacturing is to survive long term. But we aren't there yet.

To address your initial point, I think you're off on the original demographic. The TV series targeted families with kids, not teenagers. The target demo was probably 8 to 14; Catwoman and Batgirl probably kept Dad interested. As a general rule, those in their 50s and 60s will have more disposable income to buy expensive toys. It's one thing to appeal to the younger generation and get them interested in playing pinball. But going to a barcade and dropping in $10 or $20 to play from time to time is a lot different then buying a machine to play for free at home in your gameroom (which you probably designed to make you feel like a kid again).

Yes

Most were pretty recognizable and not risky choices just based on theme --

MM - Monty Python and the Holy Grail
MB - classic Universal monsters
ToM - classic magic theme
TA - re-skin of an incredibly popular layout