You've made at least two mathematically illiterate errors in that quoted text:
1. Testing that double-hashing fulfills some criteria you have prechosen, says nothing about security against cryptoanalysis which your criteria has not considered.
2. Securing a password by iterated hashing (because it requires the dictionary attacker to perform the iteration cost on each dictionary trial) says nothing about the increased vulnerability of collision cryptanalysis. You are conflating two separate issues of security.

Of course double hashes can't be applied to securing passwords as in case #2 above. That requires 1000s of hashes. Double hashes would be a silly joke in that case.
So thus you've admitted that double hashing adds no protection against a computationally bounded adversary (i.e. the only kind of adversary that exists in the real world). So why did Satoshi add double hashing to Bitcoin

So thus you've admitted that double hashing protects against length attacks, but length attacks can't occur in the Bitcoin. So why did Satoshi add double hashing to Bitcoin

Don't tell me you arrogantly claim your grand insight is enabled because Bitcoin does hash(hash(M)) instead of appending part of the input to the output of the first hash(hash(M||M')||M') as is always done for HMAC where the idea for deploying double hashing originates.
As I interpret TPTB_need_war's explanation of the potential vulnerability (and I'm the canonical source of such interpretations, lol) due to a Boomerang differential attack, that Satoshi adopted the incorrect way of doing double hashing is precisely what makes Bitcoin open to the hypothesized vulnerability.
So why did Satoshi add
the incorrect form of double hashing to Bitcoin

If you were correct, then every brother and his uncle should be trying to find a cryptographer help them crack Bitcoin and become $millionaires by spending old coins that were allegedly mined by Satoshi and may otherwise never be spent if Satoshi is truly dead.
I tried to be nice to theymouse and Gmaximus and discuss in an open forum about how it might be possible to break Bitcoin so that it could not make one person very wealthy. But they want to play hardball, so...
Please kindly quote my post in case it is deleted by the mods.P.S. My personal opinion is I speculate Craig Wright was hired by core to discredit Matonis and Gavin. And I was hired by myself to do the same to "core"; and I speculate "core" appears to be affiliated with the aforementioned individuals. Velvet gloves are off. No more nice guy. Bitcoin is a failed clusterfuck with 70% of the hashrate attributed to China, and one former cattle farmer in China planning to increase that to 98%. The miners and Blockstream are ostensibly colluding to put soft fork versioning into SegWit. There is $1 million per day flowing from n00bs into this raping system that ends up in miner's pockets and other connected parties. Electricity likely charged to the collective via State funded hydroelectric infrastructure. And the ecosystem has no real utility outside of gambling, scams, and other nefarious use cases.