I can add no valid theories at this point. However, I have to laugh at the thought that somewhere, billions of years from now, an advanced race of beings will be poring over the Voyager Golden Record with intense scrutiny. They will have on their supergalactic tinfoil hats, flipping insane theories out into the ether as though coins down a wishing well.
That metaphorical well will fill to the brim with nary a firm solution until, one day, a hapless wanderer trips over the answer. That fortunate individual will then connect all the dots, confident that he/she/it/they can now falsely claim having been on the right track the whole time.
Focused, peaceful discussion will ensue after this discovery, to better ascertain what should be done with all of the new knowledge. The victor will receive a token of gratitude for having made the momentous discovery, before being brutally murdered by some religious fanatic in a live, galactic broadcast.
Ancient, Earthling zombies will then come up from the dust of Mother Earth to learn the science of space travel, roving around and eating brains of all shapes and sizes until the universe is awash in the gore of empty cranial cavities and disemboweled creatures whose binomial nomenclature surely begins with the letter "¥".
After the complete and total purge of so-called intelligence, the whales of Earth will finally open their mouths, out of which will come forth the true stewards of the universe: Velociraptors. (Whales are sentient beings in a symbiotic relationship with Velociraptors. They all live together in harmony inside sub-ocean caves. We don't know this because we spend more time on meaningless distractions than we do learning about our habitat.)