The antonyms for the phrase "more well-spent" are numerous, and they include words such as wasteful, unproductive, useless, fruitless, unsatisfying, and ineffective. When something is deemed wasteful, it means that it was not utilized for its intended purpose, and resources were squandered in the process. Similarly, when something is described as unproductive or useless, it means that it did not yield the desired outcome as expected. Fruitless and unsatisfying denote failure, disappointment, and poor return of investment. Lastly, ineffective denotes that a particular strategy or approach did not bring about the desired outcome and fell short of the intended goal.