480p video needed as a choice in Roku Express setup. Not everyone has an excellent network connection.
Unfortunately, it's not going to happen. The video processing on the Roku only outputs in 720p and 1080p. And honestly, streaming at 720p takes almost the same bandwidth as 480p, so really wouldn't make a difference if you have a data cap on your Internet service.
Until about 5 years ago, you could get a Roku Express+ with composite outputs for old TVs. Those did 480i (no p since old TVs were 480i.) However, even on those models, there was apparently no way to specify 480i or 480p on the HDMI port. 480i was just a kludge to get Rokus connected to some old TVs.
Of course, you could also make a feature request, but I wouldn’t hold my breath.
I also think that Roku needs a 480p display resolution settings because I run my Roku off of the hotspot on my phone and it would be a nice feature