I know they exist, it's simply the fact that they're not usually required in daily speech, since verb conjugation gives the context of the pronoun anyway.
Yes, they are required and used. First, verb conjugation has nothing to do with object pronouns. You always need those. Second, subject pronouns may not always be required but are used much more often than they are omitted.
It's not good practice to comment with such confidence when you're so wrong.
(Side note: I thought the original quote was something like "the rain in Spain falls mostly on the Spaniards," but I can't find anything to support that. Only today did I even learn that it was from a song.)
Apparently, "The Rain in Spain." (To be clear, I would not have known that before looking it up to verify the quote.)
The original lyric I was parodying was "the rain in Spain falls mainly on the plain." (Which, again, I would have gotten wrong if I hadn't researched it.)
edit: After a few minutes reviewing YouTube videos, apparently it was prose recited by the protagonist of "My Fair Lady," the movie from which that song came. Eventually she gained confidence via that song.
I don't know, I previously lacked context for the quote, but after watching a relevant video I realize I've seen a parody of it in Family Guy.
And My Fair Lady is a remake based on the 1938 Pygmalion. I actually like the 1938 version better. All and all, Pygmalion is a play written by George Bernard Shaw back in 1912/1913.