Or... Google could open source their software, leverage the thousands of volunteers and let a giant leap be made by both, their own projects and OSM-related ones.
Google could let OSM users trace from their aerial imagery or from their street view data. That would be a massive boost to OSM. Microsoft let OSM trace from aerial.
In certain cases the Bing data is better, and in most, I think it's on par for my region (Northern California). Half of the Sierra in the newest Google images is snow-covered... not so useful.
But you're right—more would be better. I'm a little surprised MS went for it, but I doubt Google will.