The question about what Infocom would have done absent Cornerstone is interesting, but I find myself toying with a different way of looking at the counterfactual: if we posit an Infocom that successfully managed to make it through to the 90s putting out commercially-viable games, what would that have meant for the amateur IF scene?
The reason this is interesting to me is that the relatively-static Z-machine (I think specifically versions 3 or 5, though these technical details are beyond my expertise) provided a clear anchoring point for the amateur pioneers to work towards – obviously TADS isn’t as literally built on a reverse-engineered Z-machine as Inform, and there are lots of independent strands coming from fans of non-US companies like Magnetic Scrolls that I know less about, but still, there’s a lot of convergent evolution. Folks, it seems to me, were largely trying to create work that could match Infocom’s universally-agreed-upon mid-80’s high point, both in terms of technological affordances and game design and writing, and that organized the scene’s efforts, and judgments, accordingly.
But what if you muddy the waters and suppose that Infocom successfully pivoted, so that it put out late-80s text/graphic hybrids that weren’t the easily-dismissed likes of Shogun, Journey, and Zork Zero, and then further transitioned to 90s graphic adventurers that were (perhaps more literary) peers of the games coming out of Sierra and LucasArts? At that point, you’d presumably see a fracturing of what people really into Infocom-type games would see as “classic Infocom” – some would be into the early-to-mid-80s stuff that constitutes our current understanding of the “canon”, but presumably others would see the notional Legend-style text/graphics hybrids as the pinnacle of achievement, and still others (maybe the majority) would be subsumed into the set of folks working to recreate the classic point-and-click games.
In that landscape, instead of a well-defined (albeit small) community focused on creating a specific mid-80s touchpoint, you’d probably see a broader variety of efforts, with that Balkanization of labor likely hindering progress as well as siloing the kind of community excitement and support that led to TADS and Inform catching fire.
And importantly, if some more advanced platform than .z5 wound up being exalted as the archetypal experience, that would probably imply graphics would be a greater part of the equation. That would have made authoring a game a much more challenging proposition, I think, in terms of the design and technical skills required – even today, with much better tools, I know many authors agonize about how to just create reasonable cover art! And distributing, sharing, and playing these presumably bigger games using the Internet infrastructure of the mid 90s would likewise have been much more challenging and out of reach of many folks (the community would have likely been even more university-focused, it occurs to me).
Anyway, this is of course all just idle noodling. But it does seem to me that there’s a case to be made that if we excoriate Cornerstone for killing Infocom, it might also deserve some of the credit for creating the vibrant amateur IF scene that’s now lasted longer than Infocom ever did!