Objects in a data share become unavailable to a consumer account if the objects in the data share are deleted or if the permissions on these objects are altered without re-applying the grant permissions systematically. This is because the sharing mechanism in Snowflake relies on explicit grants of permissions on specific objects (like tables, views, or secure views) to the share. If these objects are deleted or if their permissions change without updating the share accordingly, consumers can lose access.

The DATA_RETENTION_TIME_IN_DAYS parameter does not directly affect the availability of shared objects, as it controls how long Snowflake retains historical data for time travel and does not impact data sharing permissions.

Running the GRANT IMPORTED PRIVILEGES command in the consumer account is not related to the availability of shared objects; this command is used to grant privileges on imported objects within the consumer's account and is not a routine maintenance command that would need to be run regularly.

Acquiring a data share through a private data exchange does not inherently make objects unavailable; issues would only arise if there were problems with the share configuration or if the shared objects were deleted or had their permissions altered without re-granting access to the share.