I remember the counter to that being 'if you're going to hit something hard enough that only a top line helmet will do then what state's the rest of your body going to be in?'
Here's another obvious counter, our lives are worth any cost, so spend all you got on a gold plated helmet with diamonds and pearls. The $100 helmet for the $100 head is nonsense.
Sport Rider magazine did a real good test on helmets a few years ago and came to the conclusion that the people who came up with DOT standard got it right. The gist of the report was that the DOT standard allowed for the plastic shell and styrofoam filler to absorb up to the point where anything more was over 8 g's and likely a fatal head blow. I like my $49 Bilt helmet but it leaves a crease across my forehead that last for an hour or two after I wear it.