if a private key to a bitcoin address has been lost, then the bitcoin in that address should, in my opinion, be erased from the market cap.
Yes, the bitcoin is lost but cant erase from the bitcoin market cap because the lost bitcoin is still stored on the bitcoin and it the private keys which can be use to unlock the funds (bitcoin) that's missing.
To make more understandable. Do you what coin burning is cause the situation is just like it.
It is published in articles that a bitcoin market cap of $1 trillion would equal around $50,000 per bitcoin. This is a substantial underestimation. If you factor in a 30% loss of bitcoin, then a $1 trillion market cap would equal around $77,000 per bitcoin.
Some article writers spread false information and the best way you wont be misleaded is through more research and asking question on here.
Losing a private key is like throwing a gold coin in the ocean.
Thats correct and this is the reason why some
metallic private keys/seed storage keeper was introduced.