Ever. Tradition and law trumps everything. Always. And forever. Which is why Rav Abraham Isaac Hakohen Kook believes that in the third temple we'll be bringing vegetarian sacrifices. (Seriously!)
Building on the idea that the aim of the torah (among its other objectives) was to slowly wean us from objectional practices, practices like slavery, Rav Kook teaches that permission to eat meat was a temporary concession, a concession that will one day be revoked. (and I say this as someone who plans to grill steak tonight)
If Rav Kook is right, and mankind does one day give up meat (the way mankind gave up slaves) our decendants might look back at us and our meat eating habits and say: "What was Grandpa DovBear thinking?! I could never do that now!"
Which is exactly what we say today when we look back at our slave-holding anscestors. Doesn't this all suggest that progress, dare I say it liberal progress, is a Torah idea?