Having been married to a builder, I understand about home construction. While many may* simply wish to have a cosmetically updated home, I have a much more intimate understanding of the mechanicals of a home and what the norm is for construction. I remain baffled that the cellar hatchway entrance had remained without a door for 57 years. The only thing protecting that area from the harsh elements of Winter was the steel metal hatchway doors. My parent's circa 1954 home also had a metal hatchway but had a wide door at the base of the stairs into the cellar, although it was a flimsy one offering little energy conservation. DX had replaced it with a steel door early in our relationship, with my parents only covering costs of material.
Here is the installed, steel, insulated door from the cellar to the hatchway. A deadbolt also secures the door, for added security. Spray foam in a can was used to fill gaps, additional insulation will be added before sheet rocking over it all. A possible entry by mice, it's good to get this sealed up.
The stairs also were repaired: 2 treads were replaced, an additional, center brace added to the stair system. Good, solid stairs now. This area needs a good vacuuming and perhaps a coat of spray on paint to make it light and bright.