A mentor once taught me that all actions taken by a company's people should be focused on making money, saving money, and saving time. This is mostly a sniff test for "does this thing we're doing make sense in some obvious way." When sniffing the value of any given team's Agile process, I usually find a notable lack of attempting to make money, save money, or save time. Often I found people are very good at spending money, wasting time, and being completely detached from how they actions contribute to making money in a meaningful way.
This sounds common-sensical, but of course in practice it's almost impossibly hard to tell if any reasonable course of action really will make money, save money, or save time.
Will refactoring help? How about a continuous integration system? A better bug tracker?
In fact will fixing bugs make/save money/time at all? Customers seem to put up with them, and it's always easier/cheaper not to bother.
Will customers leave if our product is shit? Often they won't. Sometimes they will, because a competitor's product eats our lunch.
So what's the best course of action?
One problem with Agile - and all management fads - is exactly this lack of prescience. Future outcomes are unknowable. They can sometimes be estimated, but given a huge field of possible actions, making optimal choices is incredibly hard, and there's always a trade-off between long-term and short-term rewards.
The bigger problem is that corporations and businesses are very rarely primarily dedicated to making money. Internally, the true function of business processes is to highlight and maintain a political hierarchy which supports resource concentration for senior management and shareholders. Senior management and shareholders may know what's best for themselves, and that may well not be what's best for the long-term survival of the company - not even in terms of an apparently simple metric like "Does this make money?"
Because you can't answer that question without also asking "For whom?" And it's not that unusual for senior management to choose actions that protect their status over actions that increase income.
Consider that agile is an absolutely minimalistic team process structure compared to what came before it. Maybe there are better methods now. But you have to have SOME kind of system in place, the baseline isnt $0 + no planning needed.
So, when you say that it spends money, wastes time and so on, what process structure do you compare it to?
Agile doesn't directly help you make money, save money, or save time. I think of it as a way to reveal what people are working on, including myself. If I'm working in the corner on who knows what, and as a leader you wanna know WHAT I'm working on, Agile can help with that. Agile may get me to communicate that I'm working on something awesome or something horrific, and what you do with that information is up to you.
If it's more efficient than some alternative, then it IS saving me money and time. Having NOTHING in place is clearly not an alternative. We must always have something. Therefore, whether it's saving money or time is relative as to the alternatives, or relative to whatever processes we had before the introduction of agile.
What did you have in mind that you consider to be more efficient than agile?
(Btw, I noticed you snuck the word "directly" in there, as in "agile doesn't directly help you make money…". This makes the rule of thumb nearly useless as the only people who directly make money is sales. Very nearly everything else that goes on in an organisation is in indirect support of them, one way or another.)