[tristor]

Promises to investors and a competitor's feature list define your scope, not your budget. Salaries and quality of hires are correlated (but not causal), and are directly tied to cost as a component of it, along with time. Feature cost estimation can be as simplistic as:

Running Costs + (Weekly cost of Engineers * Weeks Slated) + (Hourly Cost of Managers * Hours in Meetings/Discussions) = Projected cost / required budget.

Increasing scope causes an increase in time spent both in meetings arguing about it and engineers working to build it, which increases the time side. Increasing salaries / quality of hires increases the cost side. Promises to investors or contractual obligations to partners/customers are non-negotiable increases in scope, so directly drive how much time something takes.