Exactly which great statues are we speaking of, so we know what was being carved with what?
There’s a lot of ancient statuary dating back to the Babylonian/Assyrian periods, but these were people who had discovered copper and iron, which was hard enough for the stone they were carving (in other words, they weren’t carving granite, but limestone, sandstone and other “soft” rocks).
Polynesian cultures may of worked with harder rocks, but then again, most of their carvings weren’t exactly photorealistic. Cleavage and simple banging of a pointy stone against a flat stone can account for most of the carving. Likewise for monolithic structures such as Stonehedge. Find a big rock in the vauge shape you need, bang on it with other rocks until you’ve shipped it down to how you want it, then set 'em up.
By the time we see any real detailed carving in things such as marble or granite, mankind in those areas already had steel tools (remember, steel has existed since Biblical times) which would do the trick.
“I guess one person can make a difference, although most of the time they probably shouldn’t.”