Your misconception stems from this fact: the "best" chain is determined not by the number of blocks in the chain, but by the amount of work in the chain. Right now nodes consider the average sha256d block to contain much more work than any block from any of the other algorithms (due to magic work factors set before asics were common).
This from
https://en.wikipedia.org/wiki/Bitcoin_network "The best chain (black) consists of the longest series of transaction records from the genesis block (green) to the current block or record. Orphaned records (purple) exist outside of the best chain."suggests that what you are presenting is a major "revelation" that stands the crypto-world on its head and that therefore needs some very serious documentation supported by hard data.
That page just uses non-technical wording. Bitcoin also uses the "most work" criterion.
Work factors only apply to multi-algo coins.