The point is that one catch up to state-of-the-art-in-the-90s in CS theory with basically one upper-division course. That is not a lot from from a mathematical

The point is that one catch up to state-of-the-art-in-the-90s in CS theory with basically one upper-division course. That is not a lot from from a mathematical perspective. Till a few years ago, undergrads could contribute to CS theory research, whereas in math only senior grad students can do that. What the article is saying is that CS theory is slowly moving towards the latter model, as more work is done and the low-hanging fruits are picked off.