There have been many, many interviews with these people since 1945. They have not been, on the whole, reclusive. The Atomic Heritage Foundation has a great oral history website of people who were involved in the development and use of nuclear weapons during World War II. If you click "filter by subject" and select "Hiroshima and Nagasaki missions" and then click "apply" you will get a lot of them.

Brigadier-General Paul Tibbets, the pilot of the Enola Gay, gave interviews to the Columbus Dispatch and some of them are quoted in his obituary.

Here's another interview from a documentary he did.