Even had the 3+1 suite been any good, it would not have changed the fact that the Plus/4 is not compatible with the C64's massive library. Tramiel, as ruthlessly brilliant in business as he was, never moved beyond his mindset as a Toronto office furniture/typewriter maker of only being interested in tangible things. In 20 years in the computer business, Tramiel never understood the importance of software. Think about that.
>Of course what Commodore should have done is release a "C64 Plus" as a backward compatible system, like Acorn, Apple, and Atari did with their series, with enhancements such as more banks of RAM, faster CPU, dual SIDs, and an enhanced VIC-II with new modes offering 80 columns and a larger palette, and a better BASIC. They could have added these features without breaking much existing software.
Indeed. As each new Apple II model is compatible with the older one without having to boot into a compatibility mode, this encouraged software developers to gradually support newer models' features. An architecture that began with 4K RAM, cassette storage, 40-column text, and 280x192 8-color graphics in 1977 by 1984 supported 128K, floppies, 80-column text, and 560x192 16-color graphics as the norm.
>Instead they offered the C128 with a C64 mode which resulted in little software being written for the C128 mode.
Correct. If the Apple IIe and IIc required booting into a "II+ mode" to run older software, developers would have continued to focus on the much larger II/II+ installed base. While 80 columns had by 1983 become reasonably commonplace in terms of software support (albeit via a variety of incompatible methods), at least for non-games software, double hi-res would probably never have seen meaningful support.
Of course, Apple then with the IIgs proceeded to make the same mistake as Commodore with the 128, and obtained the same outcome in terms of sales and market acceptance. I believe that this is the result of technology advancing too quickly. By the mid-1980s VLSI had reached the point where it was possible to engineer the entire C64, or Apple II (IWM), on a single chip. This made using a single chip a temptingly easy way to provide 100% backwards compatibility, as opposed to the much harder task of extending the BIOS/KERNAL/BASIC/etc. to support new features while maintaining compatibility with, say, 90% of existing software. While Commodore never had much software talent, Apple has always been as strong in software as in hardware so it has no excuse in retrospect.