Try playing with a shoulder strap, get your thumb out of that restrictive loop and put your thumb on the edge of the keyboard as do many Quebec and Euro and Irish players. That is the way I play most of the time. This makes a world of difference.
However , if you do want to sell... 15 years ago, Savoy was actually making his own accordeons by himself. There is certainly someone who wants one.
"I had Marc Savoy make me a cajun accordion about 15 years ago."
and "Probably played a total of an hour on it over the years."
I think we might be on to something there, concerning why you haven't gotten the results you want yet . . . probably needs a WHOLE lot more foreplay than that before it opens up to you.
It's an Acadian, so I expect you can get a pretty penny for it; maybe even a shiny dime. Or I've got a similarly played, similarly mint condition Taylor guitar I'll trade you fer it. Unlike the Acadian, I expect you can be playing it expertly in a day or two . . . Feel free to give me a call at 479-502-2893 or e-mail at thehappyhalls@sbcglobal.net I also have a couple of gorgeous piano accordions I play only rarely these days that cost a whole lot more than that Acadian did new. Also much easier to play.
If you want immediate gratification though, the dobro is the instrument for you. They are fun as hell, and with that open chord, you can be playing songs in less than half an hour. Way fun.