When I weighed a jet v. the King Air I now fly, that was a consideration. I would need a type rating (not that big a deal) but insurance would also require recurrent training every six months. It's not just the cost of that training, it's the time it takes to get it done. It just wasn't worth it to me. I have commercial/instrument rating, but didn't see a need to get the ATP. I have flown to ATP standards in recurrent training, but have never done the formal training and applied for it. When you get a type rating, it is also an ATP ride is what I was told. The jet adds cost, different maintenance and more time staying current.
I was going to chime in, but this was covered very well. One also has to look at the planes: the TBM is a six seat plane with no potty. The Mustang was to compete with my plane--the C90 King Air which has eight seats, a potty and some other creature comforts in a cabin class plane. Think sedan v. suburban. The C90 has a payload of over 900 pounds with full fuel and an STC is available to increase that. I can't do that in a Mustang. More like a Citation II SP if I wish to fly it myself.
Best,
Dave