There's no technical barrier to truncating a blockchain. Just create a new genesis block and have it initialize every account balance to the balance it held at the end of the previous block chain. You could discard all the junk data as simply as that.

"No technical barrier" means nothing with respect to Bitcoin. You have to convince a large majority of Bitcoin users / miners / exchanges / services to switch to your new genesis block or other protocol modifications, otherwise your fork will die off, or at least not "be Bitcoin" as the rest of the world sees it (e.x. Bitcoin Cash, etc)

But really it's not even necessary, nodes can and do prune op_return, spent, and otherwise unspendable transaction outputs.

The point though is someone is likely to always hold onto a complete history of the Bitcoin blockchain, even if most users don't.

> The blockchain data will never be "optimized" or "disappear"

The former may or may not happen depending on how widely it is used, certainly not everyone will have the full blockchain on their devices due to storage requirements. The latter is a social issue not a technical one.

> Please take the time to learn how Bitcoin works before pontificating

One can definitely make an argument that Bitcoin will lose its social relevance in 100 years. Or 500 years. Or 1000 years. Do you see where i'm going with this?

Most of the OSes currently in use might not be relevant in a century. Most of HDDs or SSDs in use currently won't be around in a century, unless they're a part of an abstracted and clustered storage pool, which would take constant effort to maintain. Even short of the technical concerns, there is still need for social relevance - if and when it eventually ceases to be relevant, no one will care much about maintaining copies of the full blockchain, except for maybe in some museum archive.

Using a globally distributed store like that is a good idea, but it's definitely not foolproof. One of the better ways, perhaps, but maybe there are even better ones, that you or a foundation in your name controls, with properly sourced funding and preservation of data being its sole and primary concern.

>The blockchain data will never be "optimized" or "disappear" This is a really bold assumption - you do understand that core dev is still ongoing, yes?

You do understand that "infinite data on a disk" doesn't exist, yes? And as the chain goes on longer, more space is going to be needed, and centralization of the miners will continue to increase, yes?

Please take the time to learn how Bitcoin works before pontificating

Just like the Internet, Bitcoin is built on layers.

The Layer 2 technology, like the Lightning Network will fix the "infinite data on disk" problem.

> centralization of the miners will continue to increase

Ask yourself: why do miners use energy to run the Bitcoin software?

You can get paid to learn about Bitcoin with the Satoshi Passport app on iOS.

The point is someone will always store a complete history of the Bitcoin blockchain, even if most users/miners prune it.