I don’t think St. Olaf’s price is actually very different from many other solid LACs in the Midwest. I bet you would get similar COAs at Beloit, Lawrence, Gustavus, Kalamazoo etc. where $35K-$45K final COA after merit is possible.
I think the difference is that Carleton markets itself as a “national” LAC along the lines of Bowdoin, Williams, Pomona etc so doesn’t discount, while St. Olaf despite drawing an increasingly national student body still draws mostly regionally.
ETA: Upper Midwest LACs are often a real bargain. St. Olaf especially so. It’s just a great school. I see a lot of my Carleton classmates sending their kids to Olaf now.