There's no guarantee you'd have double your salary now if you'd worked harder in your 20s. A lot of salary in tech is just location. A few years ago I nearly doubled my salary just by moving to a new city and taking on a new job there.
Also I love working for smaller companies even if they do pay less than big tech. The opportunity to work on greenfield projects and actually have meaningful input into the direction even as an IC is extremely cool to me.