The marketing of legal services through branded pens and breakfast seminars will be no protection against a sustained attack from the Big Accountancies. Their turn-over dwarfs the legal firms and the "they won't because they won't" hope that companies will only buy legal services from dedicated law firms sounds very Kodak.
The quality of the service may be reduced somewhat for now but for lower-end Legal services, price and ease is key. It is effectively the "disruptive technology" argument applied to services. Over time the quality of the newcomer increases and, possibly, eventually dislodges even the finest quality incumbent product.
I think we can expect the mergers and increasing management professionalism in the Legal Industry to continue for sometime yet to fend off this mismatch.