Did people doubt that this was theoretically possible? Seems self-evident to me. The interesting thing will be seeing it in the real world rather than in a controlled environment where they deliberately made all devices on the network have a known vulnerability.
There’s a difference between speculation and measurement, especially since you’d have people making arguments like saying that open models aren’t powerful/fast enough to work. Demonstrating this is a useful warning to everyone (most of the industry) who’s been slacking on internal defenses because they don’t think a well-resourced attacker will target them.