[TheRealPomax]

On the consumer side: not until people can actually afford casually dedicating the bandwidth necessary to deal with multiple 4k streams. Because either you need a truly monumentally liberal internet plan for sending uncompressed 4k at a normal frame rate, or you need a hardware encoder (baked in to your motherboard or discrete graphics card, or as separate purchase) to make sure you can send compressed 4k. And that only covers the sending part, you need to also receive and have the hardware capable of smoothly rendering the 4k video stream you're receiving.

But more importantly, on the industry side: given that live TV broadcasts are still 1080p, the answer here is almost certainly "not until the broadcasting world decides live 4k by default is even remotely worth it."