Futur units utilizing Wifi 7

Since they haven't added WiFi 6 support yet, 7 is probably years away. You are absolutely an early adopter, since few people have more than Gigabit at home. Most homes rely completely on WiFi, although I'm in agreement with you that wired is the way to go for most devices. 

All that said, you are forgetting the purpose of a Roku device. Their primary use is for streaming from the Internet, and so far there's practically no online content that needs more than maybe 25 Mbps. Those of us that have home media servers have asked for Gigabit Ethernet for years with no response from Roku. And even using 5 GHz 802.11ac the highest speed I can get on my Ultra 4800 is around 230 Mbps. Even playing a video via USB, so no network bottleneck at all, I can't play a 250 Mbps test file without buffering. The Roku hardware simply can't handle video content much over 200 Mbps, so there's no real benefit to a faster network connection.

I have no doubt that some day in the future Roku will announce a device capable of 8K (I think there might be a couple of Roku TVs that do now), but since there's no content available yet, I don't think an 8K player is in the cards for a few years yet. We've pretty much passed the usual window for any new announcements this year. And until that content is available, we don't really know what sort of network speed is going to be needed to stream at that level. Netflix can sustain a 4K video at 10 Mbps, so it's entirely possible/likely that 8K still won't exceed Fast Ethernet speeds.