It’s difficult to go up against collective wisdom once it becomes widely accepted. Such is it with the notion of a flight to quality to Manhattan’s Class A office space. The notion — born of the successes that state-of-the-art office towers such as One Vanderbilt and One Manhattan West had in leasing up in the face of a trend toward reduced office demand in New York and other cities — is feeding decisions about what to do with older office buildings, ones that feature just plain old offices, the ones commonly referred to as Class B or commodity space.