4K is nice for geeky fun (even so 8K).
Currently most of the developed world does not even have enough bandwidth to stream it properly. Meaning: yeah, you can shoot it, process it (oh god I can’t imagine After Effects and Premiere rendering stuff for 4/8K before I grow old, but … it’d work), and watch it on your own 4K/8K tely (or put it up on youtube to showoff you did something in 4K, where 95% of the viewers will watch it downscaled on their 24″ Monitors in 1080p …)
If one has money to buy 4K tely now, I can’t see the problem throwing $3000 for a camera now – and then, when a 4K model comes out, dump it and purchase a new one?
And B) how LARGE would be your 4K target audience in the next, say 2-3 years? 😉 Yeh it will grow, but come on 😉

Started out doing photography at the age of 6 using an uncle's old 1940 kodak brownie box camera. At 15 years of age, I decided to buy my very own 1975 Praktica SLR camera. I now shoot with a Nikon D850. I do unpaid TFP and commercial paid work.