I don't want them to have control over what players do. And the fact some server is operational for over 20 years doesn't neglect the fact most games don't last that long. Once the sales get below their expectations it will most likely be dead.
The Steam Workshop is better with no quality control?
There are some really nice assets there but they are totally unusable due to no LOD, have too many polygons, missing dependencies that no one can find because they were pulled from Steam for one reason or another. There are version updates that are difficult to manage, and besides once you download your content isn't it yours to use anyway?
A product being around 20 years from now depends upon the genre and passion for the game not only by the company but also the userbase. If it's yet another online blood and guts shooter game, well then yeah that's a good point.
With a program such as Cities, or Trainz Railroad Simulator, or some other long-term game/program, that's different. When I was using Cities 1, I had cities I carried over from the very beginning and updated them with each interim version usually without issue because I use very few mods. With the Trainz routes I have created, I have one that's still operational that was created in January 2004 in the very ancient TRS2004 and I had just gotten the game in December 2003. My construction was a way bit off but that's another story and it surely brings some laughs with the overly done hills and poor but usable track laying. Going through and renovating the older baseboards from this route has brought that to the current state and I easily merged parts of the old into the new revised version which is far larger.
Take a look at N3V's Download Station aka the DLS.
It was launched in 2002. There are currently close to 750K assets as of today available for download. This is all user-created content and typical of user-created content some of it is better than others. You pick the content-creators you like and download their content. The advantage is for the most part, nearly all the dependencies are there and through their system are downloaded automatically. What doesn't work is when people host content elsewhere and then that starts the dependency hunt. There's also error-checking on uploads and their Content Manager has further error-checking. With each version update, there has been increasing error-checking that flag more and more faulty assets, much to the chagrin of many users because what was supposedly working before now doesn't, but that's a whole new bag of wax to unwrap.
N3V's system also has automatic versioning built-in. When the content-creator follows the rules, an asset can be automatically obsoleted and replaced without needing to delete a previous version first and unsubscribing from the author, hunting for .xml files, and doing other crazy things to remove an asset or mod. This has worked flawlessly and the only time asset is broken is when the content-creator has created a buggy replacement, or requires a user to replace an asset manually, with program updates being another issue if the author hasn't updated his scripts to work in the new updates. This is all done through a unique ID system called the KUID system, or Kewl User ID. This is a multi-part ID system that is associated to every asset installed and is set up as follows: KUID2:USER_ID:ASSET_ID:VERSION. The previous KUID: is obsolete due to a quirky and sometimes messy implementation, but is still fully supported to allow older assets to be used.
The complete content management system is done via their Content Manager. You can sort assets by the usual name, type, install date, and so on in addition to further filtering such as on the DLS, obsolete, needing updating, etc. Obsolete assets can be easily deleted leaving the new ones in place without affecting the rest of the operation, and finally asset modification, repairing, and editing is done through Content Manager
So, I beg to differ that a program won't be around in 20 years from now. Heck, if you think about it, we may not either given the current times.
