It's true that when you get desperate, you might get results.
But what also often happens is that people set unrealistic goals, fail to achieve them and so get discouraged and give up.
Part of the thing of goal-setting is understanding this in people, that not everyone has 100% perfect willpower. They need little achievements to make themselves feel good, help them keep going.
For example, we get a lot of unfit, overfat and weak people pop up here or in the gym and want some training advice. We could talk to them about benching 100%, squatting 150% and deadlifting 175% your bodyweight as goals for a year from now. But when they come in and struggle just to lift the bar once, those goals seem impossibly distant - they just give up and go.
Instead, we give them goals like: run 5km (however slowly) without stopping, and do 24 pushups, supine pullups, situps and squats, and to do that within 12 weeks. And we begin them with (say) 5 of each movement, add 1-2 movements each week. So this week their goal is (say) 10 pushups, 10 supine pullups, and so on.
Most people have very ambitious goals when they first come to the gym. And 90% give up within 3 months. The standard method of training is giving up. We make that more likely by suggesting that people should have unrealistic goals and get desperate.