My impression is this is gradually going by the wayside for all brands, and that's not just on the manufacturer support side but also the breadth of custom roms

My impression is this is gradually going by the wayside for all brands, and that's not just on the manufacturer support side but also the breadth of custom roms available to different brands/models. The exception is if you get a Pixel which has 'top tier' support for custom roms and then there's a sharp falloff. Past that point you're into "your mileage may vary" territory with how much feature support is retained or degraded by the rom, and if you're bothered if banking apps require a phone with play integrity or playing hide and seek to pretend it's unaltered. This is likely just my perspective, but it seems that there's less to be gained from custom roms in recent years anyway as smartphones have matured and the rated of change has slowed. Plus there has been a trend among some brands to offer longer OS support lifecycles, of which Samsung seems to be one of the best for android.