Changing is natural, some people think to change their jobs because of many reasons, if one day you decide to leave the research domain, which job you choose.
First of all, thanks for sharing such an interesting question based on a useful ability of planning the so-called "Plan B" to all of us.
As far as my potential "Plan B", I might think to consider the idea of making myself useful in the fields of Management, such as Environmental Management - Engineering Management or something like that.
As a Project Manager... who knows... or occupying a position in Leadership.
Best regards,
Antonella
PS: just to smile: well, as I am also a violinist, I could continue to compose music for violin, piano and viola during my break at work.
I would dedicate myself exclusively to teaching, I could even go to the field of secondary education. I also like the field of primary education, but in that case I would have to spend some time previously training in that educational field that is so specific.
Thank you for sharing, i think that in some cases changing the profession doesn't have a relationship with luck of love or passion, maybe be one day you discover that you are more useful in doing something else and more happier.
If I had to change my career at this stage in the life cycle, I would use my expertise in economics and finance to transfer money to those who need it most, namely the disadvantaged in society.