The only strategy I can see from Canon atm is to make people believe "it's expensive, it has to be stellar".
Maybe. I'm going to reserve judgement. The fact that Canon brought out the 40mm f/2.8 'pancake' lens at $199, then slapped a rebate on it to knock 25% off the already low price, suggests they know how to make and sell a cheap lens that delivers good IQ, if they want to aim for that market segment.
I'm sure Canon Marketing has done their homework. Remember that the main determinants of price are cost the market will bear and expected sales volume. Whoever the 24-70/4L IS is targeted toward (and honestly, I'm not really sure who that is ), it's possible Canon does not expect to move a huge volume of them (unlike, say, the 24-105/4L IS or 17-40/4L), and has priced it higher to compensate. Revenue generated is a more important metric than units sold.