I really don't know if it's fair to say that it's too complicated for kids today I think in reality pinball is just plain too complicated and too hard period to attract a super wide audience. There are no levels in pinball -- it's on hard mode from the first plunge. Rules are super complicated -- even when I just played The pinball arcade I had to go back to the rules page over and over and over again -- and these were for the simple williams games. Both these things are huge barriers to getting into pinball -- of course it's these same things that make it so fun and addictive once you do get it.
Back to the kids -- , I think pinball has been non-kid relevant for close to forty years, basically once the atari 2600 came out. No longer were games constrained by needing to generate revenue by quarter sucking -- and therefore high score chasing became a minor aspect of the hobby/activity. I remember our big christmas present one year was a beat up Genesis pinball machine. We all thought it was neat, but were kind of confused by it. I think it was only when we got in our 20's that we first revealed the robot underneath the table -- it was very shocking! I'm 52 and even back when I was a kid pinball machines were these weird/hard devices that frustrated me whenever I tried to play them compared to video games. I felt like a moron playing them.
Anyway, long story short -- I don't think this is the best example of how kids these days are different. If this was 30 years ago, I think you'd have the same experience.