After he fell out of the pro scene he became way more interested in chess variants than vanilla chess (more specifically his Fischer Random Chess). I can't imagine being at the level he was at, where you needed to hundreds or thousands of hours memorizing and practicing openings... so not surprised he appreciated a game that valued more on-the-fly decision making than heavy preparation.
You don't actually spend 100,000s of hours memorizing openings. You study the basic opening principles and key variants, but for the most part it comes very naturally. You play 100,000s of hours of chess, and EVERY chess game has an opening.
