I agree with Tate Elliot - enlist the help of her friend. I'll put money on the fact that her friend did not start out with the machine she's now using. If her friend is a true friend, then she'll encourage her to look - and hopefully help her find - a machine that has some of the features she'd like.
As a fairly new quilter myself, I understand your wife's feelings. Because she's 'mastered' that machine (probably with a lot of help from her friend, lol) she thinks that's the only machine she'll be able to use.
As her confidence grows, and with the proper encouragement, she'll eventually realise that all machine are fundamentally the same - but some have more bells and whistles than others (that's not to say there isn't a difference in the build quality of say, a Mercedes and a Jeep - there is) but that's a whole other can of worms, lol.