In the 70s, the white cabinet versions were typically the cheaper ones.
Today, they are often considered to be the most classic and timeless designs and may be
more sought after, perhaps because their “neutral” appearance has a certain minimalism
to it, and they will blend it better in many room designs than f.e. a wrong wood sort would.
Rare? – Well, certain products seem to be rarer in white than others.
Relatively many white Beomaster 1900/2400 can be found, as can the matching Beogram models, but matching white Beocord 1900s and 2400s are far between.
Martin