Now this typically years after an initial release and the new server typically doesn't contain the expansion packs. I suspect this kind of notalgic gaming will continue. My suggestion is that with each major build and release they backup and store it for years to come. This way if this kind of revenue stream becomes a possability for ESO that the backups be made avliable to do it.
Example, Warcraft, for example would likely garner a lot of old subscribers if they launched a retro server, without all the expansions and reprogessed through them. But they never did the appropriate backups to make such a thing happen.
Anyway, I point this out now because I fully expect ESO to last for years to come and at some point, offering up a nostalgic version of ESO may be a good revenue stream.