Good solutions respect the constraints instead of pretending they do not exist.

A plan that assumes away the real constraints is not a plan. It is a wish with steps. The budget really is what it is, the time really is limited, the people really do have other commitments, and any solution that requires those facts to be different will fail at exactly the point it meets them. Good answers are shaped by the limits rather than in spite of them.

Write out the constraints plainly before designing anything. Then check your proposal against each one. The version that survives will be less elegant than what you first imagined and considerably more likely to happen.