What does RTS mean to you? Warcraft3? C&C? Well, those games aren't RTS, they are RTT. Real-Time-Tactic games. Stratregy means "hmm, should I build a new tank division or should i improove my anti-air defence? Perhaps i should try to stage a coup in Spain to attack france from the south? If i put Rommel in comand of my panzer army, they will probably break throu the Maginot line and then they will reach Paris within two weeks! Or maybe I'll just nuke it." (From Hearts of Iron 2: Doomsday)
or "Oh, so Bohemia wants to join my alliance? that's good, then i'll be able to diplo-annex them in five years. What is this? The evil French decleared war upon me togwether with the papal states and Venice? Time for revenge! Let's just raise an army of 15000 infantry in Tirol so they can capture Rome, and why not use a mercenary army to halt the french forces so my allies Spain and Prussia may attack from north and south? Oh, i forgot about their colonies in north america" (Europa Universalis 2)
That is strategy, not "I'll sent my pesants to chop some wood so I can build a barrack and train 10 footsoliders and 5 archers. They will crush my enemy at the other end of the map!" or "My army of 15 tanks will create a diversion from the north while I garrison the buildings surrounding their base and attack from the east with the reast of my army" That is tactic, not startegy.