I personally don't think Apple and MS have the power to take Android down with lawsuits. The parts of stock Android that infringe can be re-written by the open-source community to get around the patents. In fact that is why I don't think Google has been sued- either stock Android does not infringe or they are scared that if they put out in court exactly what it does infringe the Android dev community will fix the problem in a week.
I DO feel however that Android device makers ARE infringing with their custom OSes. Every one sold- Samsung, HTC, even B&N- have very custom interfaces that probably infringe on some patent or another.
And that is where these device makers are caught between a rock and a hard place. Like akugami said, Apple and MS basically set the standard for modern OS interfaces so the only way these device makers can be "familiar" enough is to rip them off. Otherwise the customers have problems using the devices and they fail in the market.
Take for example pinch-to-zoom, which I bet Apple has patented. Everyone now expects that action to zoom. Nerds (to get around infringement) might be happy to shake-to-zoom, but if the device makers expect regular people to buy in they need pinch-to-zoom.
In the end the device makers need to decide how much they need of MS's and Apple's interface design choices for comfort, and pay for the ones they need. If they don't want to pay then TODAY they need to set a new open (as in consortium owned or whatever) standard that does not infringe and market the crap out of it so that people will still buy their devices. Its a cost-benefit analysis.
The only lawsuit that scares me is Oracle's, but I personally believe it does not have much merit mostly based on hope. We will see with that one.