This article has not dated well at all. Compare IE's security track record with, er, just about any other browser and it's clear that sometimes throwing away a teetering house of cards and starting again is absolutely the best thing to do.
(I kid, I kid.)
In Apple's case the re-write idea turned out horribly and the only reason they made it thru is because a former founder had created a startup years earlier and had a working OS that Apple could buy and use.
Apple is hardly a poster child for re-writing software.
It looked cool, in the late 90s.
Of course those are just the starting points, from that a lot has been reworked/improved and a lot has been added.