And it's referring to how they did things in ARR which is a dramatically different game compared to what we have now.
Watch the following:
https://www.youtube.com/watch?v=UXvfHESJw5s
Note how whilst I DPS on the heart phase and dot gaols etc, yet didn't bother to maintain even aero on Titan. I was used to these Titan carrys dragging out and I knew this one would even more so because we had 2 tanks and soso DPS. It's pretty much as Yoshida says in the documentary, I needed to play the long game with my MP.
However, that was 5 years, 2 expansions and countless changes ago tho. That style of play is massively removed from what we have today. Resource management ceases to be a the issue it once was as you start getting 320+ gear, it takes wasteful amounts of aoe healing or hugely aggressive aoe DPS to seriously threaten your MP pull now assuming things aren't going horridly wrong elsewhere.
A good comparison might be saying that a TV documentary showing servants walking infront of cars with warning flags is still relevant because it aired on Dave last night. The documentary might be recent, but it's still discussing a bygone era.
I might have snorted a bit when I saw this =(