Alphabet at least returns capital via huge buybacks that effectively act as dividends, but with more tax efficiency.

Why would it be in fashion? If you want the money, then sell your shares and don't cause a taxable event for everyone else.

A dividend is one mechanism for financial rigor and focus, since shareholders don't like dividends being cut. Having large piles of cash lying around is a temptation to use it for sub-optimal returns, or even worse, empire-building.

Another reason is that the shareholder functions more like an owner. Without a dividend the managers have a less clear responsibility to the shareholders. Maybe they act wisely, maybe not, but there is no real constraints on their behavior. The stock then acts more like a lottery ticket than owning a business, because you don't get anything out until you sell. Whereas, if the company pays you something because you own shares and therefore you own a piece of the profits, the ownership structure and the management structures line up better.