Note that the Trezor asks for the seed words in random order. There are 24! different combinations of the seed words, only one of which is valid. An attacker would still have to try on average half of the 620,448,401,733,239,439,360,000 possible combinations, which would take quite some time (by design). Using an offline computer for recovery is only necessary when you want to keep using the same seed. If you lost your Trezor, you should switch seeds anyway, and using an offline computer to move the funds is perfectly safe.