It's also based on a very generous assumption about performance (1 billion permutations per second) so probably a lot more than 19 million years. Extrapolating o_e_l_e_o's example takes us into billions of years.

OTOH perhaps some very resourceful entity (a government, or Jeff Bezos) could potentially use millions of supercomputers and do it e.g. in 1 year... the question is - to what end? It's a very narrow use case, doesn't break Bitcoin protocol, and how many wallets are there that could be hacked this way and would justify the likely cost of $trillions?

At any rate, I wouldn't advise scrambling the words as a safety measure, tempting as it may be due to the above. The focus should be on keeping the seed physically secure and easy for the owner to recover.