lowepg isn't wrong about on-location pinball for kids: there's a Shrek at the local Chuck E Cheese and the kids ignore it. It usually has a random credit on it if not an abandoned ball in the plunger. it's a shame, but they'd rather put their coins in a machine that goes "ping" and spits out 3 tickets than play a full game of pinball.
but it's not that kids today are fundamentally incapable of enjoying it. i don't even think it's a problem with theming or rules -- it's just at a glance, its purpose isn't obvious, whereas the redemption games are instantly understood. i can't blame a kid for putting their coins in a machine they understand versus one they don't.
when kids come to my house, usually they are curious about the pins. but they simply don't know what they are. my daughter (age 6) likes to play, so she will usually initiate some rounds with her friends. they will ask me how to play and i'll tell them, give some basic hints like "if you send the ball up that ramp, it will go down to that upside-down area underneath the blue window" or "when the ball comes out that scoop, hold the right flipper up and see if you can catch it" etc). they do have fun. had a girl about 8 years old play for an hour, and cry when her mom made her leave. and her 6 year old sister played 2 full games on all three of my machines. with a little bit of guidance and instruction, these games were as cool to them as anything they'd seen.
but without me (and to a lesser extent my daughter) there to tell them about the games and sort of get them started and giving them hints and stuff, tell them about various goals, they would probably lose interest in a couple minutes. if they had just encountered these games in an arcade, they would never have been interested.
so i guess my point is what it takes to get kids -- or anyone, really -- into pinball is someone else that's enthusiastic about pinball to be there to introduce the game and get them started and actively help them see some of the cool stuff. no casual player has ever read a rule card, or ever will. and young people don't instinctively understand anything about it. they may not get that the flipper buttons are on the side, or that the lights are anything other than random, or that some of the stuff on the playfield is interactive and that there are goals and modes and such.
pinball is still a very cool games for people of all ages and all skills levels, but it is not a self-starting thing. it requires an ambassador.