to avoid a double spend there needs to be a database to store information about who owns a particular amount of cents/satoshi/pennies. over time this database will grow..

so even if it was not a blockchain, a distributed ledger with transaction history would still grow.
imagine it this way:

take the US cent. each cent would have a digital signature to identify it, to make every cent accountable and able to be linked to a particular person. every 10 minutes 325,000 cents are created (equivalent to 25BTC at $130) and no more then this amount can be created due to each signature being designated to a particular coin in some fashion.
that is 325,000 new database entries every 10 minutes. and then when small amounts of them are moved between parties the searching the database for each signature, and swapping ownership in a way that is impossible to double spend or manipulate and then validate the completed transaction went seemlessly would cause huge delays.

knowing that in just 4 years 68,328,000,000 entries will need to be made just to identify every cent created WITHOUT even including a transaction ledger. imagine the database size.

lets say a cent needed a minimum of 12 digit hex code as its signature, to ensure no duplicate transactions (id recommend more though)

12bytes=819936000000bytes
=800718750KB(divide 1024 not 1000)
=781951.9MB(divide 1024 not 1000)
=763.6GB(divide 1024 not 1000)

this is the size of a database ONLY storing data of fresh made coins over a 4 year period, equivelent to making 25x$130 every 10 minutes.

no transactions...
now imagine it had to be 8 decimals that needed to be accountable...

satoshi nakamoto has actually made a brilliant way to secure double spending, make every satoshi accountable and ensure that manipulation cant happen... at a far far far less storage requirement then a FIAT system would need

Already. Follow the link in my signature.

Dear OP, with all due respect, I couldn't make it past your third item before immediately putting together this response.

Do some research and then come back to revise your post.  I suggest reading the white paper and searching through btctalk threads.  You have fundamental misunderstandings and an obvious lack of background on the available resources.

Take care!

Yes we need the blockchain.  While not absolutely perfect, it's a completely elegant solution for forcing millions of self-serving, mutually antagonistic, error-prone humans to come together and agree on a mutual history.