Think about it like this. A customer is the entity that exchanges money for something they value; like a good or service. That's usually your manager. Or in the case of OP the promotion committee. (Many times it's both your manager and the promotion committee). They are the ones who directly control your money (raise, bonus, promotion, etc).
With that perspective in mind it makes sense to manage your career as a business where you're doing things to increase the rate at which you deliver value to the entity which can trade money for that value.
Many of the setbacks you faced are very common when trying to run your own business. The customer changes their mind, the market shifts the goal posts, you realize you're focusing on the wrong things. Like a business you have to constantly change your strategy and adapt to the customer; not the other way around. Why? Because the customer can very easily get their goods or services from someone else if you can't deliver what they want.