"How long before most or all meetings are streamed via the channel?"
I frankly don't see this ever happening. My guess is that the channel will be primarily for non-JWs and extra-meeting material.
The WTS is all about control and obeisance. The incessant in-person drumbeat is essential to the indoctrination that fuels their arrogated authority. Risk the chance of sheep using their DVRs to fast-forward through Public and Student Talks on obedience and loyalty to the organization and FDS? or Accounts "Report"? or, OMDG,... blowing through the entire Watchtower Study?
Not to mention the temptation to binge-watch recorded meetings when/if they "have time" --winkwink.
Uh...fuhgeddaboutit.
If anything, I expect the beatings on "not forsak[ing] the gathering of ourselves together" to increase exponentially, if that's even possible given the amount of bleating on the subject that presently prevails.
AMNESIAN,
Captive 7/1972 - 2/2001