You may want to move the post to the Argosy motorhome section to get more attention.
What you have is called a Roto-dinette and they are like 'hens teeth', very desirable and will have some resale value if you remove.
That said many people have removed them over the life time of their vehicles and a regular pedestal seat base can be installed, but even the highest fixed pedestal will require an additional adapter for many seats.
The biggest complication is the drivers also swivels and so, although there are many many replacement seats available most will not rotate past the steering wheel.
There are many examples of alternate seats in the Argosy motorhome section of the forum, but just an example....