It's not about capable vs not capable. It's about improving our chances. Once you've got a squad signed up I don't believe tactical tweaks make much difference, as the squad is built to suit a particular style of play. Or it might have been built with no style in mind (like when coaching/recruitment staff are replaced in quick succession) but will still suit one style over others. It would be foolish to change to a style that doesn't suit the squad, just because another (differently composed) squad is having more success with that style.
I think we are already a chance of winning the comp (about a 10% chance). But if we remained a 10% chance of winning the comp we would only win one roughly every ten years. Certainly better than our (average) probability of winning since 1986, but if we want to be better than 10% chance of winning we need to improve the squad.