Why are there no turn based vidya as deep as RTS games?

Uh, what?

Depth is admittedly difficult to quantify, although it must be said that in the end, strategical component boils down to choosing the time scale during which you want to achieve your strengths (timings, rushing<->playing for the lategame) and operational/tactical component is just different varities of force concentration. Doesn't matter if you do 6 clicks a second on average, there's roughly the same amount of core strategic and tactical decisions that are essentially the same (selecting half of your forces, making a new control group, queuing a few movement commands, selecting the rest of the forces, placing them to another control group and moving them to the opposite side, and then going 1a2a isn't really a dozen different decisions but one decision to flank, something you'll find direct tactical equivalents to in games as abstract as Chess and Go).

However, complexity (in the sense of quantity of mechanics) is more quantifiable and in that regard real-time games (pausable real-time has more common with turn-based games than stereotypical RTS) don't even compare. For example, the number of factors in combat resolution formulae in some wargames can be in the different order of magnitude to RTS games.