:-D
Isn't it great? I can really relate to your story. I struggled for quite a while, thinking I just couldn't do it on my little Kenmore. Took a class at a LQS. In the very first class, the teacher picked MY machine to do a demonstration for everyone, and it was BEAUTIFUL. So, it wasn't my equipment! I just kept doing it, adjusting this and that, using different needles and threads. At some point, it just seemed to "click" like you said. Mostly I think it is your own mindset -- gotta be relaxed! All the other things affect the stitching a little bit, but not as much as your groove. (However, I won't FMQ without my supreme slider!)
Once I realized I could do it, I did invest in a better machine, mostly to get a larger throat space for working on larger pieces. I got a Janome 7700. But my old machine is still on standby, mostly for toting to classes and workshops.
Happy quilting - have fun!