You keep repeating this, and it remains unsubstantiated, and likely wrong. Canon doesn't improve DR because there's no business need to do so, and it would cut into their profits to do so. They're making very nice money as things are. They will hold onto their high-DR tech until the market requires them to use it. Even Pentax has pro-sumer sensors with higher DR than Canon; you can't expect me to believe that a tech giant like Canon can't keep pace (in the lab) with Pentax. No, Canon DR will improve when it must. Right now they're trying to keep manufacturing costs down to increase profits, just like any for-profit entity would do.
Put another way...Canon is milking their loyal customer's wallets rather than focusing on producing the best product they're capable of producing. Case in point: Well, numerous options here but most recent, the 6D. Arguably the worst offender in this regard. DPreview put it perfectly:
"Overall, though, it's difficult to shake the feeling that the EOS 6D simply lacks the 'wow' factor of its main rival. Whereas Nikon seems to have taken the approach of taking away as little as possible from D800 when creating the D600, Canon appears almost to have gone the other way, removing as much as it thinks it can get away with at the price. The result is the kind of conservative, slightly unimaginative design that's become the company's hallmark."
Canon's "approach" does not inspire loyalty, rather it makes me question whether I want to support such a company at all. Why would I not choose to align my $$ with a company that pushes the edge of tech, etc in imaginative ways instead? Aren't those qualities appealing? As in the D800, D800E removing aliasing filter option, HDMI video out, D600. Sony is coming on strong too.
And look at Canon's pricing. I just have no idea what Canon is thinking any more. None.