That is a good point.
Whilst I like to tinker, I don't like that everyone I know manages to screw up even the most user friendly system and then call me up day and night with stupid questions.
And whilst I have, actually, changed a set of pistons and big end shells (first car was an MG BGT) I couldn't ever imagine doing it on my Passatt. When I feel like tinkering with engines, I tinker with my 60s lawnmower. Its engine is tinker-friendly. It had to be, as it was (and is) always breaking down. Modern engines remove the ability to tinker but also the need> to tinker. The people who miss attending to 50+ grease points of a weekend still can - they just lovingly maintain old cars.
If you miss an old interface, fire up an emulator. If you want to hack an OS install Linux (in a VM parhaps?).
I think the opportunities for writing up a clever and powerful little app in your spare time is greater today than it ever was, and there are so many different ways to do it.