In the future years when "study of video game history" becomes a thing, people will be able to examine and analyse old games like SimCity 2000 by actually playing them as they were. Since they have been archived and preserved by wide distribution.
Then as you get further into the future maybe you start to come across games where you have to say "sadly the only existing copy of the server code was lost in the great github fire of 2020, so all we can show you is this archived footage".
You mean the tens of thousands of videos that will be posted. Historians will have no shortage of source material.
I'd actually argue that the videos are more valuable as they show first hand how the game was played at the time. Think a recording of a long-forgotten instrument compared to the actual instrument, which is more valuable?
One solution may be to propose an escrow system.
A neutral non profit (or several) sets up an entity which exists to collect software binaries and/or source code from companies under strict NDA.
At some event, either after a period of time or at the time in which the service based on that software ceases to operate; the software is released to the public (either for free or for some payment to the escrow entity).
In return the company gets a "no abandonware" sticker it can use in it's marketing/branding which gives consumers confidence in their purchase.
And I forget what the excuse was for Command & Conquer 4.
It's just DRM first and foremost.