So apparently there's like 4-6 million bitcoin that are lost and gone? Just curious if there was any ideas or plans to update the protocol to replace the lost bitcoins if there was a consensus, if that is even possible.
Very unsure about the numbers - but sure, there are a lot of users who have to be willing to lose their bitcoin and in most cases it is the user's own fault.
The quote from Satoshi can be interpreted as meaning that every Bitcoin user is obliged to keep his private key well and safely. Losing your private key means you will lose your bitcoin - there is no guarantee of replacement, meaning you are fully responsible for the security of your wallet and bitcoin. If you can no longer access your wallet because you lost your private key - then you should forget about it forever and go back to the point satoshi said.
Lost coins only make everyone else's coins worth slightly more. Think of it as a donation to everyone.