Yes, I'd say that is true. Just like with AG brewing, you use a base malt for most of the beer (DME or LME in extract brewing) and then get the color and flavor of the specific beer from the specialty grains.
I don't think it has to do with flavor compounds being killed off in evaporation. It's just that it's very hard to nail down a flavor profile or recipe when you use "dark malt extract" because you have no idea what's in the dark extract. Crystal malt? Certainly. But how much, how dark? No telling.
I wouldn't necessarily use Pilsner LME, since I don't use pilsner malt for many of my beers. I'd just use "pale malt" or whatever the basic 2-row extract is. For DME, I always just used "light", and for LME, I just used the "light pale malt" or equivalent, unless I wanted the flavor of pilsner malt or Munich malt. If I needed Munich malt extract for a batch, that's what I'd order.