Power without the means to deliver it means the power is useless. Similarly, if the technique lacks power it is also useless even if you manage to execute it perfectly.
A good martial art technique is one that can be delivered with power. This is akin to sharpening the limbic knife. Such a technique can be said to possess killing power.
Learning a martial art without knowing how to sharpen our tools means we are only learning half an art because at the end of it the techniques could end up being half effective. The main problem with techniques such as strikes is that many times they are difficult to test convincingly.
For example if you can chop a red brick in half it means that your hand has the necessary hardness and power. But it does not mean that you can use it against a resisting opponent. On the other hand, if you managed to strike your opponent but he is still standing then your technique is practically useless unless you are using it in a points tournament.
Proper learning of Tai Chi Chuan means we should train the overall requirements rather than just focus on a lopsided aspect such as being able to push an opponent. Let’s say you managed to push your opponent off balance. So what? Can he still come back for another go? Certainly. If this is a real fight what does your ability to push him off balance mean? It only means you have the strength to shove him. Does this mean that you have the ability to deliver injurious techniques? Not necessary.
However, this is the present reality of many Tai Chi styles. They have the techniques but for unfathomable reasons you never see these techniques used. When the techniques are used they seem to work only on non-resisting opponents. Many times the outcome does not look convincing and observers cannot be blamed if they doubt that Tai Chi is ever an effective combat art.
If we are satisfied with an unrealistic approach to training Tai Chi as a combat art well then fine. If not, then we should re-examine how we train the art. Ultimately, the failure of the art to protect us when we really need it is really our problem. We can blame the teacher, the style, etc but in the end it takes two hands to clap.