Let's think about co-authorship credit this way: Which is the more morally "correct" choice to make?
Give Credit: A lot of people are already calling for it. It's something that makes sense in terms of this movie and the published run given the incredibly similar content. The only person that might be "harmed" by this decision is adelikat himself, and as far as I can tell the only "harm" that would come from this is him not getting as many player points.
Don't Give Credit: This is the more "logical" choice given that Phil's input doesn't actually appear in the movie, but in my opinion that just means we need to take a look at the rules for co-authorship and make some changes to them accordingly. This seems like a narcissistic choice if anything, as Phil's run wasn't surpassed in any way, shape or form aside from this run having an extra stage. Phil's strategies and optimizations were still used in this run. This choice essentially robs Phil of his record that wasn't even beaten and would likely make some people lose their respect for adelikat and/or whoever ultimately makes the decision for obsoletion.
These are just my admittedly biased thoughts. Take them as you will, but I do agree that Phil should get credit if his movie is obsoleted.
If anything, I think there isn't enough co-author credit on the site. I always appreciate runs like the
new Final Fantasy glitched run that credit people for things other than providing actual controller input, even if
that amount of "input" is minimal. There's something more... realistic about it, I suppose. None of my runs would have existed if it weren't for the work done by runners (both TASers and RTA) before me, and looking back I feel bad not crediting them for how much they contributed to my runs, even if it wasn't active contribution by the authors. Sure, maybe it's a bit overkill to credit EVERY idea ever given to you*, as the co-authorship lists would get ridiculously long, but I feel like ideas that make up the core of a run should have some credit attached to them.
As for the matter of obsoletion itself... I can't say for sure whether I'm for or against it. There's too much weirdness surrounding the ROM and game in general that makes me think it's different enough for a different publication, but at the same time I feel it'd be redundant to have both runs published when this one does everything the published run does and more.
*this mentality is the only thing keeping me from whining more about metal force
