So the big WHAT IF is, something happens to the blockchain.
That is an extremely unlikely thing to have happen. Every full node in the world currently has a complete copy of the blockchain. You would have to destroy all copies globally to destroy "the blockchain".
Can nothing ever happens to the blockchain,
While I suppose it isn't technically "impossible", it is unlikely enough that it isn't really something worth being concerned about.
and that no matter what, this blockchain will survive even if all of humanity has disappeared?
Why would we need the blockchain if all humanity disappeared? Why would we care what happened to it under those circumstances?
Will it never grow so big that it can never fit into a computer's harddrive?
It is impossible to predict how big data storage will be hundreds of years from now, so it's impossible to predict if the blockchain will
ever grow to big to store.
At the moment, the maximum block size is 1 megabyte, and the protocol adjusts so that blocks are created approximately every 10 minutes. It is possible today to purchase a 6 TB Western Digital desktop harddrive for less than $300. At a rate of 1 MB every 10 minutes, it would take 114 years to fill the single hard drive.
Beyond that, it is possible to set up an array of hard drives. As an example, you could load up a Drobo B800fs with eight 4 TB hard drives. this would give you access to 29 TB of storage. That's enough to store maximum blockchain size for the next 550 years.
Larger capacity drives and larger arrays are likely to be created in the next 500 years, so it is reasonable to assume that storage of the blockchain for the next 1,000 years shouldn't be an insurmountable obstacle. Beyond 1,000 years, I think it is okay to let future generations decide for themselves how they want to handle commerce.
Will blockchain.info never be put out of service and never expire so that even in year 2530, we can still check up on Satoshi's genesis block that he never spent a single coin from that block?
Why do we care? Blockchain.info is jsut one company that has decided to create a block explorer. There are nearly a dozen of them out there. If they all go away, you are welcome to check your own blockchain (or hire a programmer to do it for you).
Food for thoughts everyone, have a happy Sunday.
Not much thought was put into your post, and there really isn't much food there. It's mostly just a waste of time and a bunch of ridiculous rambling stream-of-consciousness garbage.