Computerworld does do an excellent job of laying out the traditional business case for allowing flexible staffing (the high cost of replacing employees who leave, the positive impact on morale at firms that offer flexibility, the institutional knowledge that stays with the firm, the increased productivity of happier employees.) But the article focuses mainly on the IT profession. I would imagine that senior partners at many major firms would find ways to distinguish the practice of law.
The business case for allowing flexible work arrangements in the law is similar to the IT profession. But the attorney/client relationship is often a more personal relationship and anyone arguing that flexible staffing makes business sense in a law firm must also address the issue of client service (i.e. how to ensure that clients who are paying top dollar are getting the high level of customer service and the high quality of legal representation that they expect.)
Certainly law firms can save on recruiting and training if they find creative ways to reduce turnover. However, they also need to be more creative about finding ways to staff deals and litigation matters in a way that ensures the client always has access to a professional that he or she trusts.