My opinion is that the 1952 Topps Mantle is way overpriced. There are too many of them available to sustain the current price.
Full disclosure - that has been my unfortunate opinion for the last 30 to 35 years. Which is why, as I sit here with over 500 Mantle items in my collection, I do so without the '52 Topps Mantle and with no hopes of ever getting one now.