What do you mean by "originally"? It looks like it was introduced as 80 bytes here, so it had only been 80 bytes for a year or so: https://github.com/bitcoin/bitcoin/pull/2738
I recognize the commit where the limit was lowered, though I don't believe it was actually released before being raised again.
The commit that is referenced by this comment is "script: reduce OP_RETURN standard relay bytes to 40" https://github.com/bitcoin/bitcoin/commit/8175c790eb
There you can see that it was originally 80 bytes.