I used to work in project management where we had the concept of the triple constraint. This means that any project has three key factors that can be altered or controlled. They are the cost, scope and timeframe. By increasing the scope, you also need to increase the cost (resources) and/or the timeframe. The three factors are tightly interrelated. You cannot change one factor without altering at least one of the remaining two factors. Put another way, you can please some people with increased scope but upset other people with increased cost and timescale.