No. The hassle of getting that to work is probably way harder than just getting things to work on Linux in the first place.
I think that Valve will eventually put out a libvalve which can be used to target a number of linux specific integration points for typical windows programs.
Wine already runs many windows binaries, without modification, on linux. Often times when wine does not work on a given binary, the issue can be resolved by patching wine, again without touching the binary. It seems like it should be relatively easy for someone who can modify the binary source code to resolve any bugs that wine runs into (probably exposes subtle flaws in the game code in the prosses).
The other issue I can think of is performance, but my sense is that the win32 API pipe is not a bottleneck in almost any program, so that is likely not an issue.
Nothing is preventing them from doing both. Dealing with nonworking wine games is incredibly frustrating (and often fruitless).
But I can see it working. In addition to being able to fix issues in the software itself, they are also working with a known hardware configuration and they can sandbox each wine instance.
PlayOnLinux already helps doing the latter, to the point where it lets you use separate wine versions for each sandbox. Much better than using synaptic to jump between different package versions.
I hope they'll stick with native versions, though.
I think that Valve will eventually put out a libvalve which can be used to target a number of linux specific integration points for typical windows programs.