No interpolated colour can be better than "perfect true colour" ...can it?
Nobody claimed that a Bayer CFA image is 'better' than a micro-step (or a color-wheel with a monochrome sensor) capture.
Tri-chromatic (R/G/B) color capture is still a relatively rough approximation of the full visible spectrum reflectance ...
In that sense, even micro-step sensor capture is also 'interpolated' color, although more predictable than from a single Bayer CFA. It does require extremely constant continuous lighting, where temperature and long exposure time are enemies of delicate artwork.
Of course, although it produces a more involved workflow, stitching with down-sampling can produce even better results. For recurring jobs, it will pay off to use a contraption like Ted describes here. One of the immediate benefits is the higher level of control over the lighting of the artwork, because only a part of the image needs to be lit and lighting angles are constant for that relatively small area of the total surface.