Stock buybacks are tax efficient dividends. Boeing has been paying dividends fairly regularly since 1937, so paying stockholders can't really be the problem. Executive compensation is kind of a red herring too. If you don't like what the executives did, it probably reflects more on the choice of executives rather than the compensation of them, but you could maybe make an argument about how compensation incentives were setup.
MCAS and unbolted door plugs feel like two separate types of problems, IMHO. Both of them can be tied to Executives and culture, of course. MCAS comes from a desire to skirt regulations --- hiding automation from pilots in order to reduce certification requirements is a design error. OTOH; the unbolted door appears to come from production / rework corner cutting; the design is sound, the written process is sound (I think), but written process was not followed in order to meet schedule pressure.
You can have a company culture that encourages skirting regulations and cutting corners in production regardless of dividends/buybacks and executive compensation.
