Netflix 4K streams seem to top out around 25Mbps and I'd guess other services are comparable, so 1Gbps is still a lot of bandwidth for even large multi-streamer households. I think a lot of families will reach the limits of cheap, basic wifi routers before they start actually pushing against their bandwidth caps in these situations.

My issue in the past with cable gigabit service was the relatively tiny upstream bandwidth of 20-50Mbps. This made for some challenges a few years ago when suddenly everybody in the house was on Zoom all day long.