He was not a knight, he was the Holy Roman Emperor. Those don't go broke from that (he went maybe broke to bribe the prince electors to vote for his grandson as successor). There was a huge jump between nobility and the high aristocracy (Dukes+). They did not buy armor for protection but to flaunt their wealth and prestige. The Royal Armory in Vienna is insane with plate armor in heaps of gold and expensive decorations. I think some Habsburg king inherited a large collection of expensive high aristocracy armor from a cousin.
Henry VIII's armors are in the same vein. They have stuff even good plate armor usually did not waste time on to make the armor even more protective and then increased the price / effort tenfold with decorations, gold etc.