Hmmm. Theoretically, I would think the opposite. In a real time game, data is rather consistent and the code can be optimized for fluid game play. Turn-based could be a bit different since the end of turn could result in a ton of data needing to be sent/received.
I doubt it. Real time online games such as FPSs have to constantly send vectors data and player inputs in and out to every players. A turn based game client merely has to send "unit A goes here, unit B goes there, crank up research allocation to X" each turn (every few minutes then) and that's about it. Everything is processed either by the server or the game host and the outcome is redispatched to clients.
At worst, the server might be a bottleneck if it got a really low bandwidth but I don't see how that could be a problem on SD's servers.
I dunno, that's just an assumption on my part, but I really don't see why Elemental would need a big ass network connection to run properly, has long as there are no graphic/sound resources and tons of mod scripts to download. And even then, that could cause a slowdown at game launch but not thereafter.