They stated they will need Cloud for bigger games while people could host games on a smaller scale. Even with enough bandwidth i dont think a computer would handle calculating everything for 40 players while rendering the game at the same time but for like 8 players or so yes.
Well decades was more an expression but yeah for me Dune 2 is considered the “first RTS” i spent so many hours on that game. Few years later multiplayer RTS came out and since then nothing has changed that much. Just look at Starcraft vs Starcraft 2, if you remove the graphics (only eye candy) its almost identical to Dune 2 in terme of gameplay. For me the only company thinking out of the box was Relic by releasing Homeworld in 1999, it’s still one of the best if not the best RTS i’ve ever played but never been as popular as StarCraft or C&C. On the other hand RPG and FPS evolved during that period of time. DOOM was released in 1993 and was using a lockstep model then Quake and other games began to use a client-side prediction. At first its was chubby but now that system works pretty well and allow way more liberty in term of gameplay and more and more up coming titles are “always connected” allowing people to join your game at any time, for the good or the bad, you decide 
But lockstep will never allow these kind of things