It cost at the very least the salary of a software engineer, though most likely a lot more. Autodesk is not some passion project of a group of volunteers who just want to keep it up. At large companies, I have seen few models of how to run public facing legacy services that don’t “align” with the company any more and as a result there is very little interest in them. They are all expensive in terms of personal and always a potential PR disaster to manage. Doubly so if it’s something that requires moderation like a forum.
You have the “there is a dedicated team for ‘legacy stuff’. They just inherit all dead end projects in the company”. If you are gonna have that model, that teams scope is ever growing, and so is their size. It’s not a shiny job either. “I maintain projects no one cares about” is not interesting or shiny and most good people will move to something else.
There is also the “since you started it, you own it now” approach. Where the virtual team that started a service, will sort of own it forever. It’s this thing that just hover over a team’s shoulder forever. Though “forever” usually means until a manager comes along who is loud enough about not wanting to deal with that shit anymore. It only causes issues when things go down, break, need updating, etc and they don’t want to work on that anymore.
There is the “the ownership of this random ass service will fall wherever we randomly draw and redraw random organizational lines. It’ll keep forever bouncing between random teams as no one cares about it, and no one wants it, and everyone argues that “it actually belong in fabric because it’s the only remaining consumer of their v2 APIs”, “fabric thinks this is more business layer because its main audience are end customers”, “business unit thinks it’s actually more UX as it’s running on the same domain”
And there is always the looming PR issue when an eventual issue happens, a ton of infighting over the lack of clear ownership and once they are over that, the person who has to fix it has no idea what this thing is and needs to get up to speed. Then you get a post on top of HN or Reddit or twitter etc saying “{Insert multimillion/billion dollar company random service} has been down for a week” and a lot of people like “seriously, they can’t figure out how to run that? I run one just for my ham group and it never goes down”
Why bother is usually the final approach.