I've made my living as an auto technician since 1984.
Yes cars are more complex and more computer controlled than when I started.
And no a scanner doesn't tell you what parts to replace, all it does is points you toward whatever system or subsystem is malfunctioning, i.e. fuel/ air ratio, ignition, emissions etc.
And now we are dealing w camera systems and radar systems that are tied to the brakes, airbags etc.
I spend more time digging through technical bulletins and wiring diagrams than I do working on cars.
Most of the BS is there to start with due to mandates from the government.
Quite honestly I personally will never buy a car that has all this crap on it.
My daily driver is a 98 BMW M3 that has 215k on it and my 2001 F250 has a 7.3 in it.
It's got 195k on it.
They'll keep getting repaired by me as long as I'm physically capable of it, then I'll pay someone to do it for me.
