I don't think a more expensive machine will change your skill level. I might make it easier to do somethings based on features but people can be phenomenal quilters on basic machines. I have gotten better over the years but I feel it is because I takes classes and try to learn as much as I can. I have made nice quilts on all my machines even my mechanicals

Buying a new machine does want me desire sewing for a while and not having to hassle with issues of an old machine can improve my attitude while sewing...but your skills are yours and I bet you will bring home ribbons on any machine...but you could enjoy it more until the novelty wears off!