Thanks for responding!
Just wanted to correct you a little bit for the record: the darker hair color and decent thickness is actually my baseline from 2016. The towhead was actually from abruptly stopping minoxidil in May 2017, which made me shed like crazy.
Attached photo illustrates it well, left is from 2016 before starting any treatment, right is in summer 2017 after being off minoxidil for like 2 months. The shedding started about a month in and it took me a few months after restarting to regrow my hair, but it came back even stronger.
Needless to say, I think minoxidil helped me maintain for all these years as well as regrow some hairline (right now I'm shedding so it's not apparent but the hairline corners improved from baseline in 2016).