Well, the online multiplayer element anyway. I am not a PC gamer as such and so I have never played the games you mention, but even I know that there are no games in the list that are even moderately comparable to Diablo II and Starcraft in terms of longevity. Those two games are iconic PC titles with a huge fanbase/following even today.
While I have many complaints about Diablo III, I was never afraid of Blizzard shutting down the servers, and that definitely factored into my purchasing decision. As you note, they have been running the Diablo II and Starcraft servers for well over a decade.