You perfectly expressed what I feel (and tried to say in my comment below). To emphasize on "always bet on software": As seen on the landing video of the (marg

You perfectly expressed what I feel (and tried to say in my comment below). To emphasize on "always bet on software": As seen on the landing video of the (marginally failed) attempt today/yesterday, they are having issues with the dampening of their control software during precision landing. While the field of control software is hugely complex, once the parameters are known, it is trivial to set these values and (later) tweak them. You cannot do that with a (largely) mechanical system. Furthermore, it's easier to run simulations with different sets of control parameters than redo all the FEM-et-al. stuff needed for a modified mechanical design. If ULA wanted to take a slighly different approach than what they proposed here (e.g. when the first tests don't work as expected), they'd basically need to redesign the whole propulsion "stage". SpaceX can alter just their software. [As always, it's not black-or-white. ULA may also fix (most of) their issues with software updates. SpaceX may need to add more fins or legs, re-distribute weight, or require more fuel for the landing. That does not invalidate the point above, though.]