This is somewhat of a speculative question...
Amiga's 1985 Original Chip Set is inherently a 16bit architecture (the data bus is 16bit, registers are 16bit, the blitter itself is 16 state machines running in parallel, and sees the memory as 16bit words). This architecture could have been trivially extended to 32bit, which would have given twice the bandwidth without touching the overall design of a machine running synchronously to the video color clock.
The 32bit architecure arrived rather late in the form of the AA chipset (which also has a memory controller that do 2 cycles "fast page" RAM access, thus working, along with the 32 bit bus, at 4X of OCS's bandwidth).
Is there a technical reason I can't see of why Commodore did not go immediately for such a trivial improvement?
[I'm interested in technical reasons, rather than strategic (e.g. lack of retro-compatibility) or considerations on Commodore's "management". ]