I think they did - I used to have an MSI gaming laptop years ago with a GTX560M if I remember correctly, and that used to throttle every several seconds, so every game you played stuttered. This one - not a single slowdown, but if you open it it has like 10 heat pipes and two fans that sound like jet engines - but it clearly works.
I'm glad to hear at least one manufacturer is trying. I can't imagine myself buying a gaming laptop again, perhaps for my kids when they're old enough, but I stick to desktop now.
My main drive in choosing the MSI I did back then was the thinness and lightness, which was counter-productive to good cooling performance, mine had a GTX970M but was about 1cm thick; the bottom of the case got so hot it would burn you if you touched it after a while of gaming.