I've considered a PhD because this is very much a field I want to get into, but I also don't really want to be a traditional software engineer anymore. However, I'm also mid 30s and my undergrad degree isn't CS. To get into a PhD program, I'd probably need to get a CS masters. To get a CS masters I have to take at least a year or two of undergrad classes (expensive and time consuming) just to get to a place where I can apply to a masters program. I'd also have to spend a year or more applying. Between masters program, then applying to PhD program, then finishing PhD program, I would be in my early 40s. I would also likely be taking a pay cut from my product manager career now, and I would lose out on a ton of income over the course of my PhD program (probably close to a million dollars worth).

It just doesn't make sense to spend 7-8 years of school for only 20 meaningful years left of my career when I finish.