Two points:
One, Apple blocking this is a win for all of us, not because the government is unable to get into bad guy's phone, but because it fixes one more way for anybody to get into any of our iOS devices. I said the same thing when Apple patched various vulnerabilities that the jailbreak community was using to gain access - eliminating vulnerabilities is good.
Two, if I were the guy from Grayshift, "gee, we don't know how to get around this" is exactly what I'd say right now, regardless of whether we had another plan/angle underway or not - the clock on the limited sales lifetime of any next device they make starts when Apple learns of some new way in that they've worked out, so you wouldn't want to start the clock until you announce sales of your next-gen device.