Why is Corton so inexpensive?

Vigne au Saint & Rognet? Some solid producers exploiting them.

Yes, lots of different exposures and altitudes (and, presumably, soils) in Corton, as a map shows:

Love that site, great info, just wish it had been updated in the last decade.

Which of the other ones should be grand crus and which should be premier crus?

Jasper Morris recently did an hour long video on this topic. Howard’s views seem to mostly align with his: