Why save more and spend less?

Whenever I read on blogs making saving more and spending less their owners' New Year resolutions, I wonder why not choose another route?

Why not make earning more a resolution?

That way, one could save more without saving more, if you know what I mean. Say, you used to save 10% of a monthly salary of $8,000.

If you achieve your target of earning more, say a monthly pay of $10K and you still save 10%, you would in effect be saving more in absolute terms.

Also, with a higher pay or more income, you needn't spend less. You may even consider yourself Scroogie if you spend no more than what you did when your pay was 20% less!