I'm pretty sure we have discussed before that if the developer can really stop ongoing development (also whatever other "efforts") and have the platform succeed then it seems plausible. That's a big 'if' though.
Why can’t it shift to a donation model (a la Monero) when the corporation exits. The key developers who were employees of the corporation, then continue to work for donations (or because they have so many tokens).
I can't rule out that it is possible but it is a very difficult transition. The cultural shift from being employed by a corporation (steady job, benefits, etc.) is enormous. Many people literally won't be able to do it because they are supporting families, etc. and really do need the stability that comes from being funded by investors. If the corporation shutters they will likely go get another such job where they can be paid a steady income by investors (or customers in the case of a non-startup).
Volunteer/donation/etc. projects like Monero sometimes work because they self-select up front for people interested in working in that structure (the rest never join), and even then there is a lot of filtering as people leave. Only if arrivals exceed departures over time does the model work (as it has for Bitcoin and Monero and some other open source projects; none others really in the cryptocoin space), and it isn't guaranteed that will continue indefinitely (or as long as "necessary") either.
In a sense I think the problem you are running into here is the same sort of problem that a lot of ICO/token projects run into (Steem included) when tying themselves in knots trying to avoid being 'securities' and in the process ending up with very distorted incentives. It is important to recognize that the models that fit into 'securities' exist and have been codified by securities law precisely because those are actually very effective models to pay for investment (by which I mean actual work which produces something of longer-term value) while generating a return for the investors (those who pay for such work). Everything else is quite Rube Goldberg-ish by comparison, and most will fail. For every 10 (or 100) claims of "disruption" of anything, say 9 (or 99) are just broken models that don't work.
Experimentation is certainly fine though. No other way to find that one truly disruptive model.