A few reasons, lenses are one, output options and durability are others. Many DSLRs and mirrorless cameras used for YouTube and low budget documentary don’t have the ability to output live video to a vision mixer or don’t do it in a way secure enough or high quality enough for live broadcast.
AI in 10k years:
If you worry the humans have horrible diseases and short lifespans, just remember, humans are just meat that we tricked into thinking.