My second Mac

Forget about OS X then, and think about the evolution of a computer from a 128K 68000 through a G4 with a gigabyte of memory. There are still applications that will run on the last version of OS 9 that were written for the original Mac. Mac users would typically have many times the number of applications than a Windows user, mostly because most had no installation requirements other than dragging the app onto the system. Drivers and system extensions were easily added by putting them in the Extensions folder inside of System. The way some of them worked (patching into system calls) sometimes resulted in system conflicts. The biggest problem in the 68K Mac world was a holdover from the earliest days of trying to fit into a tiny memory footprint. The flat 68K address space was segmented to create position independent code chunks that could move around as the system compacted memory. Unfortunately, the data space was also segmented, so the APIs often had 64K restrictions on data areas. PPC Macs got rid of that, and went to a flat memory model, which made programming applications with large code/data footprints MUCH easier. The big problem with the MacOS was there really was no architecture. Features were tacked on, including things like two different shared library architecutres on PPC because they evolved through two different devlopment groups. In the end the API was a "Mactintosh Mystery House", with dead-end APIs, and APIs that were bloated and ridiculously over-engineered (Comm Toolbox, for instance). Adherence to backwards compatibility really was why it was impossible for Apple to come up with a replacement for MacOS until someone (Jobs) finally cut the cord. This was impossible from the bottom up, no one at the top was willing to have old applications break en mass.