Why are headings still magnetic?

Bob Moore wrote:
Andrew Sarangan wrote
So, I still don't agree that navigation systems have
advanced to the point where we can abandon the
magnetic based instruments.

Hmmmm....I wonder how we used to navigate 'over-the-pole'
back before INS? Hint....Grid Navigation, an unslaved
DG referenced to true north.

I don't claim to know anything about navigation over the poles, but if
it is as simple as you say it is, why do we continue using the
magnetic compass for every-day navigation? My guess is that it must be
complex, difficult, expensive or unreliable.