Most universities already have systems to host research long-term. Most researchers are just too lazy to use it. Also, I would place more money on a university being around longer than Github if I was worried about longevity.
I agree that University archives present another opportunity, particularly among the "first-tier" research institutions in the US. One problem is that many University archives are paywalled or require restrictive licenses. Another is that these archives generally do not accept submissions from outside the University.
Let me turn this around on you. Given the availability of University preprint servers, what's the value of a service like arxiv?
Up until now, there have been many places to permanently store your public scientific research objects, so long as you were willing to use a Creative Commons license. Similarly, there were many places to freely host your software, so long as you didn't need a permanent store for your scientific code.
The GitHub-ZENODO partnership is the first web application to bridge these two needs. An earlier attempt with Figshare almost got it right, but failed to support code licenses (everything at Figshare is CC BY). This isn't the only way to host or cite your code, but it's definitely a good default.