Nothing. Buybacks are a way to return cash to shareholders, just like dividends, with different tax implications.
In your example the company has used the share buyback to return 50$ to shareholders. If it wanted to do it evenly it could even do a stock split first turning every 50$ share into two 25$ shares and then buy back one share from each person. That would be functionally equivalent to doing a 25$ dividend per original share but have different tax implications (capital gains are cheaper than income taxes in most places).
Nothing. Buybacks are a way to return cash to shareholders, just like dividends, with different tax implications.
In your example the company has used the share buyback to return 50$ to shareholders. If it wanted to do it evenly it could even do a stock split first turning every 50$ share into two 25$ shares and then buy back one share from each person. That would be functionally equivalent to doing a 25$ dividend per original share but have different tax implications (capital gains are cheaper than income taxes in most places).