I agree with this, but
I also think that a snapshot server would be useful, although I am hesitant to say that it should alternate with other things. I would not like to see the snapshot server, while acting as a snapshot server, be in complete chaos mode, as I think some valuable things can be learned by having it in creative and giving players the option to /(game)mode into and out of survival, because it allows people to explore new mechanics easier, such as determining the best new-version villager breeder and villager market layouts. Since we have two-or-more cores, then I don't see why we could not do both an archive server and a snapshot server.
Also, if somebody discovers a reasonable way, then having the archive server such that a 1.13 client could connect to each world, but each world would, in fact, be running the version of Minecraft that it ran on back in the day, then that would be a nice bonus.