Earlier quoted context omitted.
None of the tech really mattered, not much anyway. What Apple really got with NeXT was Steve Jobs' vision, along with a more seasoned CEO better capable of realizing that vision. Whether Apple had gotten BeOS or NeXT didn't really matter all that much in comparison.
This is demonstrably false. MacOS Copland was scrapped in favor of a descendant of NeXTSTEP that became MacOS X. Hundreds (thousands?) of API calls in both Desktop iOS development are prefaced NS_ ... that is NeXTSTEP
Both Jobs and Gassée were both forced out by Sculley who alot of people credit with driving Apple toward the mediocrity that defined it in the mid 90s.
The other big factor at the time was the fact that BeOS ran on PowerPC, and NeXTSTEP did not. NeXT had done some work to produce their own hardware with dual 601s, but never shipped it and abandoned that work to focus on the IBM PC hardware. This meant that the first few years of the Apple/NeXT merger were spent just getting NeXTSTEP running on PowerPC.
The biggest buzz of the time was that even though Steve's return to Apple had killed the growing Mac clone industry, maybe Rhapsody would run on x86 hardware. There were rumors all over that they would make this happen, although they were many years too early, as Apple wouldn't make that switch until 2005.