Correct, and well noted!

When writing the Whitepaper, Satoshi clearly didn't envisage the issue with a longer chain having less work, as I have described above. The code to change from height (longest chain) to chainwork (chain with the most work) was implemented in 0.3.3 in Jul 2010, as you can see here: https://github.com/bitcoin/bitcoin/commit/40cd0369419323f8d7385950e20342e998c994e1#diff-623e3fd6da1a45222eeec71496747b31R420