Not sure about that. Go back a generation, and most car were very easy to change the oil by crawling under the car. Most cars today, it's impossible to easily do it if the car isn't on a lift.
They optimize the placement of major components and systems, like engine block, gearbox, steering, suspension. Then they look at what space is left and figure out where to put the ancillary systems. They aren't going to compromise the placement of the gearbox just so that the oil can be changed by a home mechanic. They're not going to mess up the weight distribution just so the starterotor is easy to replace.
Space is at a premium, and home maintenance is never going take any precedence over optimized packaging.
