"So what keeps a company, when winds shift, from being nimble enough to shift with them?"
Answering to Wall Street. Going private would give Dell tremendous flexibility without the risk of shareholder activism in the form of class action lawsuits. It offers opportunities to pursue long term strategies without worrying about quarterly dividends and pundits' predictions.
If Dell can go private, it is a sign that someone sees a long term upside or profit from liquidation. The former seems far more likely than the latter.