I think if the NSA want in they don't need to bother with stuff like this, and if Apple were forced to compel they wouldn't be documenting anything related to it
exploiting adversaries is also a way to protect your citizens.
I'm not saying that the NSA has any involvement in this situation, but clearly their strategy is sometimes to undermine security. It's not their whole schtick, because of NOBUS, but still part of it.
https://www.schneier.com/blog/archives/2017/07/zero-day_vuln...
Really, the NSA's history of hoarding zero days is so well documented by now that it's surprising to see the tinfoil trope get wheeled out.