Modern German cars are not harder to work on so much as less forgiving of shortcuts. They want the correct fluid specification rather than something close, coded batteries rather than dropped-in ones, torque-to-yield fasteners replaced rather than reused, and a scan tool that speaks the manufacturer's own protocols rather than generic OBD2.
Done that way, they are perfectly reasonable cars to maintain independently, and at a genuine discount to dealer labor rates. Done the cheap way, they punish you for it later. We do the first one, and we are honest when a job genuinely belongs at a specialist.
Not to mileage - these are frequently low-mileage vehicles. To time and to salt. A car doing four thousand miles a year still sits through eight winters, still has its brake lines and subframe attacked, and still has rubber, fluid and battery that age on the calendar rather than on the odometer.
Low-mileage cars here get sold with the assumption they have barely been used. Underneath, plenty of them have been standing in exactly the conditions that do the damage. That is why our undercarriage inspection gets booked as often on nice cars up here as on old ones elsewhere.
$79 flat call-out, diagnostic included, 7 days a week, 7am - 7pm. If you decline the repair that is the whole bill.