Depends on what you mean by "long term damage". Does Bendis wind up bringing in enough new/returning buyers who will stay with the titles for more than 6-12 months, or does he wind up alienating enough new/ returning/ and/or current readers/buyers who feel that this is truly the "last straw"?
(And, could his "writing" efforts possibly even more polarizing than things like JMS' "Grounded" arc or David S. Goyer's back-up story in Action Comics #900 were in the last of the pre-New 52 days?)