Both gemm and the doc have pretty much hit the nail on the head, but I would like to add that it's not as if this topic doesn't get revisited often, the heads of these orgs and even important people outside of them have reasonably regular meetings around what we can do together and for eachother. I think ultimately at the moment, at least for ETF and PR we have different philosophies on a few things from recruitment to technology etc. e.g. at iseries we're able to borrow a complete production suite with hardware vision switchers, a 32 (iirc) channel audio mixer and so on, while PR's focus is very much on automation and trying to do as much, to the highest quality that they can with fewer people. At i65 we had at minimum 6 people on production at any given time, with more being able to step in (for example, console helping Fill, one of our VMs [vision mixer] who has never played TF2) and that isn't including our content and social team or production assistants. At CPH we're expecting around 4 (could easily be 2/3) to be the minimum as the role of director, VM and audio eng are able to be rolled into one through automation.
Both philosophies have their advantages and disadvantages and if I'm totally honest I would like to move more towards PR's style of thinking for i67 but it's quite difficult when we also have to liaise with insomnia themselves to work out what we can have from them etc. the total set up wasn't 100% known to us until the actual start of the event since there were some issues with cameras so I'd be weary to introduce crazy new tech (or at least new to insomnia staff) if we're not certain how it'd fit in.
Lastly, after ETF moved to an organisation team structure after assuming control of the org from Wolf I've realised just how much work it is to organise even just the production for a LAN and honestly if it was the same team of people planning for both iSeries and CG people would be burned out very fast as they would essentially be working all year round, CG planning starts pretty soon after iseries and iseries planning starts basically as soon as CG is over since CG is on the same weekend as the earlier iseries event, so that's when we're able to get confirmation from their TOs that they want to run TF2 and how they want it to work.