L&LD
Part of the Furniture
I suspect a lot of people have grown a bit cautious about flashing new firmware when their current versions are working for them - especially early on in the RT-AC87U's lifecycle, regressions were common in newer firmwares which only degraded, not enhanced their experiences with the router.
With this particular router, I'm of a similar mind - if it ain't broke, don't fix it.
Agree with your point of 'this particular router'.
But a bad habit to acquire, even still. (Without some risk, no rewards, ever).