[They made] the single worst strategic mistake that any software company can make:They decided to rewrite the code from scratch.
Don't throw away, reuse! I was a big fan of this theory in '99-2000 when I was the CTO of a company and yet when the VCs came in and said throw it all out, I did! Never again (he says with ominous sounds in the background).
To the point at hand, as an intellectual exercise, this new "secure" operating system is interesting. But you will have no users of it except in very limited custom applications, you will have no apps for it and, more importantly, the time spent designing this operating system from scratch would be much better spent on securing (either in code, or through procedures) existing operating systems. Linux, MacOS, Windows XP, etc etc all have the ability to be far more secure than you would ever need, and the only reason they are or are not is because application vendors need a little insecurity or else it would be brutally hard to run ("You just double-clicked an application that has not be dual signed by two trusted parties, would you like to run it?")