Thousands and thousands of years makes sense given the Ancient Egyptian stuff going on on the island. That was like 2000-3000BC so 5000 years ago now. Now, I still don't think the MIB and Jacob look particularly Egyptian, but I could see them being Roman centurions or some such that ended up on the island way back when (if they don't turn out to be "fallen angels" or some other sort of mystical beings, which is what I currently lean towards. When the MIB (as NotLocke) said "I want to go home" it kind of got me thinking of say a fallen angel (or even Lucifer) trying to get back into heaven (or something like that). I mean where else would a thousands and thousands of year old being, who spent all that time on an island, consider "home" in our present day world? Either the Island would be his home now, or his home would a mystical place (like Heaven) or a sci-fi place (like another planet (if the MIB & Jacob turn out to be aliens)) any real world location would be long gone for someone that old.