What would Amazon do with WebOS when they have already invested so much in Android? Switching would require them to abandon the app store they built. The Silk browser seems at odds with how WebOS works. All their Android UI customizations would have to be rewritten.
Look at it this way: their are about 1 million Touchpad users already out their due to the HP firesale. That's a nice market to buy, considering these people will want to upgrade to something in 12-18 months time, while keeping their profiles and all of the webOS software they bought (the app market in webOS land is thriving by the way since the massive influx of new users). I think whatever software work they would…
Also, if you think WebOS is somehow immune to the plague of lawsuits in this industry you're crazy. Nobody is safe from lawsuits. It's just a cost of doing business these days; you pay your success tax and you move on.