Because to earn dividends you must be a owner i.e. actually hold company stock.

To profit from buybacks you only need the option of buying the stock at a lower price than the buyback price.

The CEOs and other CXXs of these firms often have large amounts of options included in their comp packages.

This is why buybacks happen at market highs instead of market lows as sound management principles and common sense would suggest.

Increasing shareholder value by increasing equity value is just a pretext. The real purpose of buybacks is a swindle to funnel company money directly into the pockets of the C-Suite through what in the books appears a routine management operation.

These executives decide on the buybacks and exercise their share options just before, thus pocketing millions in company money and actually hurting shareholders.

Shareholders get the blame despite having little to no power and seeing their investments ruined and looted. Also, in many firms, a lot of shareholders are also employees.

You can find it better told here:

https://www.theatlantic.com/magazine/archive/2019/08/the-sto...