Erm, say what again?
Here's wiki for vanadium, you might wanna check that year :
The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer (passivation) somewhat stabilizes the free metal against further oxidation.
That's literally 2nd phrase there, right at beginning. Tell me, does that strike you as something to be discovered only in 2017? Or the guys who made the discover(y)/(ies) already seen VO2?
Also wiki is wrong since Vanadium is as rare as Copper. Does Copper strikes you as something rare?
Also the oxide the wiki article is talking about is V2O5, not VO2 (though VO2 was known beforehand - it’s easy to find articles about it from the 50s).
In other words: can we call "metal" anything not in the periodic table?