This approach makes sense, since they do not know what this specific vulnerability is.
This approach makes sense, since they do not know what this specific vulnerability is.
How do you know this? I'd be shocked if they don't have one or more of these devices themselves and have it completely figured out.
Apple would have to buy one on the grey market, which they may be unprepared to do
No, they would have to pay someone to do "research" for them and figure out the vulnerability. They would pay that person enough to buy one on the grey market and figure out how it works, keeping their hands clean.
The vulnerability may still be present in the allowed timeframe. This could just lead the investigators to carry around portable cracking devices to use at the earliest moment they can. A kind of technology arms race?