Yes. Started Japanese for the first time in my late 30s. I am currently around CEFR B1, working toward B2.

> I can't tell if the time constraints (family, work, life) or mental constraints are the bigger problem.

Almost certainly time, and/or motivation. I've certainly met a few people who had mental blocks to learning, but for the most part, anyone who has the time to actually study can learn a language. The people I've met who failed weren't dumb...they just didn't work at it.

As the sibling notes, if you can immerse yourself, that's the best thing. I've personally known multiple people over age 30 who went from 0 to B1 in Japanese in a year of immersion. Add another year, and you can get to B2. Of course, that's obviously hard if you have a family, etc., but you can still succeed without it -- it just takes longer.