> I think almost every board game is essentially a turn-based strategy game
The distinction between "turn-based" and "real-time" is largely perceptual rather than actual. "Real-time" simply does two things: it slices the turns down to an extremely fine grain (such that they're more "frames" than "turns"), and it forcibly makes "do nothing" or "continue previous action" the default action.
Thus, the real distinction for a designer is, "How much time do you want your player to have to make a given decision?" The more time you're willing to give, the more likely you should make it turn-based, and vice versa. This is how chess starts to resemble an RTS when you add a clock. If you pared the "time to move" down to, say, 10 seconds... it becomes hard (but not impossible, since you're still right) to argue that chess is really turn-based.