It sounds to me like there's only one way it can go from here at your current place and that's downhill. You have autonomy, lifestyle balance and like the people - yet you STILL aren't content. That speaks volumes, basically you are making excuses to yourself for staying where you are.
That said, if you haven't already obviously you should be discussing with your line manager that your increased responsibilities mean that your current package no longer falls within either acceptable levels nor market rates, and as such that you need to agree a tangible plan with them on the steps and timescale to rectify this. If they cannot sign up to such a plan, then the writing is on the wall. Given what you've written previously about staff recruitment and retention, I wouldn't hold your breath!
As for the "don't need the money" thing, speaking from experience feeling underpaid will gnaw away at you regardless of whether you actually 'need' a raise or not. Rightly or wrongly salary can act as a measure of worth and nobody likes feeling undervalued, in terms of self-esteem the number on your paycheque can matter even if the cash in your bank account doesn't. There's a lot written in management theory about money not being a much of a motivation factor for staff, but my personal view has never quite aligned to that and IMO being paid less than you deserve is a demotivator. The vast majority of my job searching over the years has been based around the knowledge that I should be getting paid more, yet I've not really had a situation where I've gone "I *NEED* to earn more money".