They can make an altcoin and voila, they'll have a blockchain.
But there's no stronger blockchain than Bitcoin's. And if that's advertised enough, organizations will come for the blockchain and will have to use bitcoin for that.
why bitcoin blockchain is safer than monero blockchain?
The network security behind bitcoin is 360,540,831.57 GH/s, that is a lot more than monero and that is why it is safer.
only because it has more users NOW. but in the future...