RTS doesn't necessarily entail the building of bases or conducting research - in fact such tropes often do nothing but distract from the actual battles. In many RTS games, the ability to properly manage the base building functions and general housekeeping is often the single greatest key to victory and often the player involvement in battles boils down to little more than selecting proper troop concentrations. That isn't a bad thing - the formula has proved to be incredibly fun time and again.
If you look at what Relic has done in the past few years, you'll note that they have clearly begun moving away from the house keeping mechanisms often present (but not always) in RTS games. Dawn of War removed the notion of resource gathering in general (replaced with strategic points), and had the player spending relatively small amounts of time managing base activities. Company of Heroes took this a step further by reducing base building to only a handful of buildings, meaning you rarely had to actually visit your base for much of anything. The result of the games was a generalized shift in focus from management of building to management of battles themselves. Combining that with a relatively small number of individual units under your command means that players can actually micromanage individual units in a battle.
Personally, I prefer games that focus more on the strategy than the logistics effort. In fact, my favorite RTS of all time was Ground Control where there was absolutely no logistics effort - the men you bring to a battle is all you get. That said, I also loved Starcraft, Dawn of War, and C&C (except generals, those filthy angry mobs irritate me to no end).
*edit*
With regards to the argument between tactics and strategy: the portion of a game that involves the actual combat is indeed tactical. Tactics, from a military standpoint, generally refers to any maneuver being done by individual combat elements. Using a leapfrog technique where one fire team in a squad covers another as they advance is an example of a tactical move. Having a company shift resources to another front is a tactical decision. As a general rule, any decision being made at the battalion level or below (for the US that's often 2,000+ men, or 30+ tanks etc). Strategy usually refers to the overarching scheme to achieve a grand objective. Taking a hill is rarely a strategic move - for that position no matter how perfect is unlikely to win the war. But it might just help win a battle.
To put that in game terms, when playing starcraft managing your units in a battle involves tactical skills. When you build a forward base, you have made a strategic decision (you have to expend resources to defend the installation, in return you hope to gain a monetary advantage over your foe). Choosing what forces to give to the installation for defense is a strategic move. If the place falls under attack, managing the battle is tactical. At some point, you may have to decide to either send more forces to the forward base(strategic maneuver), perhaps to a second location to draw the pressure off the base (tactical maneuver), or abandon the base (strategic decision, tactical maneuver).
Some games split strategic and tactical thinking fairly cleanly. The Total War series literally has different interfaces for it. During the strategic phase, you move armies about on a map, requisition more troops, order construction projects and the like. During the tactical phase, you control your army (at the company level) and attempt to crush one or more opposing armies (or perhaps, just hold your position until help arrives). Yet, even in this game the line is blurred between the two. If a battle is going poorly and it's obvious you've been outmaneuvered, the decision to stand and fight or retreat is often strategic.
In short: tactics are what you use to win a battle, strategy is what you use to win a war. It's the same basic thing only you are talking about different scales of time, unit size and whatnot.