Famous philosophers, writers, painters, inventors, explorers, religious visionaries and rulers are also remembered over millennia, as long as something about them is transmitted faithfully to succeeding generations.
Which means that in the future it will be pretty much everyone who, say, owns a Facebook account.
I doubt most of our digital records will make it that long. They are far too fragile.
I suspect Einstein might be "remembered" due to use of his name as a word: "He's no Einstein". Already plenty of people saying his name who don't know anything about the man, or his ideas.
When people no longer remembers who Einstein was, such saying would lose popularity and eventually die out of the language.
That happens sometimes, and other times it doesn't. Not many people know the word gadget is from the builder of the statue of liberty, but the word hasn't dropped out of usage. There are plenty of lingering names from people and ethnic groups that have been forgotten by most.