I think Mo does the best he can with the budget he's given. The club outperforms its payroll every year. The problem is that trying to find the best bang for buck can only get you so far. There is a certain talent level that you just can't attain without spending money. He was able to fit Goldy and Arenado into his budget but unless that budget increases it's hard to fit in the kinds of upgrades we need to complete with the best teams. Matz, Leake, Fowler, etc were all attempts to fill holes while staying within the budget. The Goldschmidt and Arenado trades happened because we had money available in the budget, neither was a bad deal as far as their contracts, and those teams were desperate to shed salary. I think there's a reason these big trades tend to happen for the Cardinals in the offseason instead of the trade deadline - because it doesn't blow the budget. The salaries taken on get factored in the same way a free agent signing would.
The eternal hope is that ownership sees we can't win a WS without more resources and sees fan discontent with the plateau we've hit, and opens the money spigot a bit. This is by the way a problem with every team in our division. I was talking with a friend of mine who's a Brewers fan and they have the same complaint. What sucks about that is that none of our divisional rivals are forcing us to become good enough to compete with the teams we end up facing in the playoffs.
Juice you did a better job of expressing my frustration. Kudos to you.