Aeroshell’s parent company has a bulletin posted on their web site, dated 22 June 2022, which says that they have located a different production site, and hope to have inventory for affected greases back to normal levels by the end of 2022. So it sounds to me that they were a bit optimistic with the date, but that aeroshell 5 and 6 are now in production again, but have not yet caught up to demand, leading to the high prices noted.
Related note: I saw a note from Hartzell, which of course I now cannot find, suggesting those operating props with Aeroshell 6 consider changing to Aeroshell 5 for servicing. This requires a placard, “Do not operate prop in temperatures below -40”. The note said Aeroshell 6 was ‘reformulated’ a few years back, and Hartzell is not happy with their operating experience since then (this was part of the reason for the change to Nyco grease). As has been previously posted, Aeroshell 5 and 6 may be mixed with each other, but under no circumstances may they be mixed with the recommended Nyco. BTW, aeroshell 22 is not approved by Hartzell, either.