You're playing irrelevant semantic definition of terms diversion. The longest-chain is the one with the most PoW in which the length is correctly calculated by cumulative difficulty.

Just because the longest-chain was incorrectly measured in the past doesn't mean that the longest-chain means today anything other than the "longest cumulative difficulty in a chain of blocks which are linked by cryptographic hashes". Do you really expect someone to write that quoted text instead of the short-hand "longest-chain".