The point in OP is that "blockchain" was not a new thing. The Merkle Tree was patented in 1979, meaning that it has been free for decades. Most programmers might never have a use for it but they still encounter it every time they use git (which is older than bitcoin).
So, if you're not aware of this, that's because it is very technical and nothing to do with cryptocurrencies.
The point in OP is that "blockchain" was not a new thing. The Merkle Tree was patented in 1979, meaning that it has been free for decades. Most programmers might never have a use for it but they still encounter it every time they use git (which is older than bitcoin).
So, if you're not aware of this, that's because it is very technical and nothing to do with cryptocurrencies.