If the games had pushed the Amiga harder and Commodore itself, than Amiga would be a lot further by now.
If you bought an Amiga 1200 in 1992/1993 and asked Commodore or it's reseller for a turbo upgrade, they would have said look around, but don't look for it at our shop!
And that attitude is what killed Commodore.
Games is what drove PC hardware upgrades. Its what really made graphics chips updates necessary in the PC world. Was a plug-in 3rd party graphics card architecture vital for amiga to continue as a viable paltform?
Well its interestingly, custom chips for consoles did not hold games back games development on them, with about a 5-6 year cycle. IMO Commodore could have released AGA 12-18 months earlier, which would have competed with SNES and Megadrive well enough, especially if they pushed the A1200CD and a 28 Mhz '020 with even just 2 MB FAst RAM and would have held onto its user base. Had they survived beyond 1994, custom chips with high res chunky graphics and built in 3D functions could have been implemented well enough to compete with a PS1 and N64 at least, so that would have retained many users. That custom chip system could have had a life of 5 years just like the consoles, as CPU and ram upgrades and mature programming could have more or less been good enough to produce quality games.
BTW: most viable? Sounds like AROS. What do i use and probably will continue to? Classic hardware.