Wouldn't destroy Apple even if they sold it for $1, because Apple never compete on price and would prefer lower unit sales/marketshare to lower profit margins. They're competing with the Nexus tablet and Kindle Fire at best.
All a very low priced Win8 tablet will do is drive any OEMs that currently support Windows 8 tablets out of business, since MS charge then $85 per OS sale but themselves nothing. If they then also sell this at a hardware loss there is no way for OEMs to compete.
Where they will struggle is app support. Who is going to write new applications for four different targets? (Win8, Win8 Metro, Win8 on ARM, Win Phone 8)? The Win8 app store is empty now and it'll still be empty at launch.







