"... make one wonder why the pinouts were not placed near the components..."
Because the same components are often used in different phones? Because the board is on one side of the phone and the components are on the other? Because adding more traces to route from a chip to a pinout on the edge can make the circuit board wider or require additional layers?
Apple employs some of the best designers and engineers in the business, but some AC here on /. thinks they know more.
"... just a matter of time before someone makes a modular phone..."
Which will work just as well as modular laptops and modular desktops. What you fail to get is that phones, like computers, are systems. Swapping out a "modular" camera just doesn't work, because on the iPhone the camera depends on advances in the CPU, GPU, and image processing chips. Just like swapping out a CPU in a 3-yro desktop rarely gives you a major performance gain, because that CPU isn't running on a system with a faster memory bus, faster interface bus, and better peripherals. Systems are just that, systems.
Further, every socket and connector you add increases costs, increases the size of the device (or decreases internal volume, e.g. battery space), and decreases reliability.