One thing I noticed about these is the price goes higher as the number of sections increases. Two or three sections used to be quite common in super heterodyne AM radios, but with the advent of FM they have four sections: two large 360pF for AM and two 20pF for FM.
As others have said, such parts have long gone out of fashion in favour of newer technologies (initially varicaps, then PLLs).
There's also a lot of junk being sold under the name "vintage", or "antique".
Sometimes it is cheaper to buy an antique broken radio and get the capacitor from it.