Bitcoins blockchain will always be there however there will be 2 blockchains like we saw with bitcoin cash and bitcoin gold at first bitcoins hardfork of segwit2x will be called B2X however if enough miners and supporters come together on this then B2X could very well be called BTC and the old (what your using now BTC) might be called bitcoin legacy or bitcoin classic like you see with Ethereum.

The amount of support for this is high though and miners do really control the future here. No one knows what will happen but so far we are looking towards a really large shake up between the two with a possible overthrow of the blockchain.