What strikes me about this list is how many of these blogs have been around for years - some over a decade. There's something to be said for just... showing up consistently.
I've been writing about building tools for bookkeepers (not exactly a glamorous niche) and the compound effect is real. Posts from 2 years ago still bring in readers who then find newer stuff. No algorithm decides to bury you if you take a month off.
The POSSE approach someone mentioned is interesting too. Own your content, syndicate to platforms. Too many people build their entire presence on rented land and then wonder why they're invisible when the algorithm changes.