Losing touch with someone is not a particularly novel or malicious thing, as pretty much all human beings can attest. This specific case was not unlike most every other person I've lost touch with; I moved away to college and then grad school, she moved to the West coast for a job, I moved out to the East Coast, etc. and somewhere along the way we just quit contacting each other as we took smaller and smaller roles in each other's life.
But she was one of the most formative educators I've ever had. I started taking lessons from Julie when I was a freshman in high school and continued through most of college, and over time her house became not just the studio, but a second home, to me and countless other students of hers. She was the first teacher/mentor in my life (as I imagine she was for a lot of others) that treated me like an adult, and her life advice was just as good as her voice instruction. I could go on, but the simple point is that she was hugely influential in my life.
And of course I never told her this. I imagine she was probably plenty aware of how much she touched the lives of those around her, but at the same time, I doubt anyone would mind hearing in detail how profound a positive contribution they've made to the lives of others. But I never told her anything of the sort, and now she's passed away.
I've got nothing revelatory or insightful to add. There's a reason things become cliches, etc. But every once in awhile life reminds you that you should probably let the people you love know you love them. So go do that right now.