Anything is possible but I really don't see it as being cost effective, at least for an actual set of stairs.
- You would lose a significant amount of cabin space
- The sliding door would need to be replaced, glass would need to be removed for stairway. Almost all of the aft wall of the salon is comprised of the sliding glass door assembly, a fixed pane on either side and a slider moving from center to port when open. You would need to remove the entire assembly and replace with a solid bulkhead and a hinged door or perform a major modification to this assembly to make room for the stairs to extend into the salon space. Moving the stairs aft would not provide an appropriate rise/run for the stairs, it could help but even when starting from the transom, you don't have enough room without extending the opening in the bridge deck forward.
- Any wet core in the bridge deck, cockpit deck or under the sliding glass door will complicate the project and these are all common areas for damage, especially in 40 year old boats.
I have seen some ladders on boats made with a less steep pitch and deeper "rungs/treads", when coupled with substantial handrails, they can be descended like stairs but I wouldn't consider them to be real stairs, not something a dog could use, for example.