I really thought mr Dell was aiming to be beaten by a better offer, and thus sell his remaining stock for a decent price. But apparently not. Dell was never a creative engineering company (apart, of course, from the financial engineering), and Michael Dell always shared an office with the CEO; it's been his show all along. The cash flow of recent years has been largely illusory; it's bought in like HP's: borrowed cash made to look like revenue by acquisitions shown on the balance sheet as goodwill etc.
I guess it's what he deserves, which is nice.