If it is any consolation, I got started on the Radio Shack Color Computer ecosystem, with the original version the the CoCo3. Back then, there was quite a bit of debate by the mid 1980's about the longevity of 8/16-bit processors like the 6809 and the 6502 / 6510 series.
Addressing a maximum of 64KiB of memory back when 4KiB was expensive seemed fine. And due to cost, picking an 8-bit processor for a design in 1980 seemed sensible. But the ability to support up to 1MiB of RAM (eventually) on the 8086 series help insure the platform's longevity, in spite of the horrible segmented memory programming model.
Companies like Motorola weren't terribly interested in backwards compatibility, preferring instead to design completely new instruction sets (like the 68K family) for their 32-bit platforms.
Addressing a maximum of 64KiB of memory back when 4KiB was expensive seemed fine. And due to cost, picking an 8-bit processor for a design in 1980 seemed sensible. But the ability to support up to 1MiB of RAM (eventually) on the 8086 series help insure the platform's longevity, in spite of the horrible segmented memory programming model.
Companies like Motorola weren't terribly interested in backwards compatibility, preferring instead to design completely new instruction sets (like the 68K family) for their 32-bit platforms.