Can private companies not offer dividends to their stock holders?
I did this once prior to an acquisition of a company I worked for and lost the money. It's pretty much a stupid move unless you are already wealthy and a founder or controlling exec with better insight and control over the outcome.
Also, when an employee exercises options and then sells the resulting share in a public company, they receive a multiple of earnings. Earnings != dividends but suppose all the earnings in a period were paid out as a dividend (they wont be of course) -- the shareholder will get only that amount whereas if they sell the share, they will receive a multiple often 10-15x or more of earnings. Most people benefit more from an exciting lump sum payout than an unpredictable drip at a time.