Modern vehicles are excessively complex?
Modern vehicles are so excessively complex, that even experienced mechanics struggle to fix them at times.
My dad was a mechanic for 45 years, (now retired) and he would fix his own vehicles in his garage during the 1970s, 80s, and 90s, all the time, and all he needed were some basic tools.
Today, you have to pull the entire engine out and/or practically take apart the entire vehicle just to replace a single part. A process that can take several days!