Horse trading

All projects are a push-pull between features and time, cost and resources (people).

Want more features?
It will cost you time, increase cost, and/or require more resources.

Want to reduce cost?
Cut features, extend time, and/or reduce resources.

Bring the project to market quicker?
Add people, spend more, or cut features.

Or, to put it another way:
Speed, quality, or cheap… choose two.