Why are headings still magnetic?

Paul Hirose writes:

Maybe someone else has already mentioned that VORs and TACANs are
aligned so their radials are close to the magnetic direction. Changing
them to true would be pretty expensive and disruptive.

They have to be changed if the magnetic poles drift, too. In some
locations this may occur as often as once every few years, if an
accuracy of plus or minus half a degree is required.

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