Maybe the task could never be done in two days by anyone, but the promised productivity of the tools led him to believe otherwise. Imagine a dozen project tasks built on these assumptions. The whole schedule would slip with no control like so many projects seem to do. Out of frustration one might cut corners and end up with an incomplete product, very much like the software releases for PCs. Another factor in the optimistic schedule is management expectations.
Managers are market driven, so engineers comply with a schedule to match.
Managers figure that the large sums of money spent on tools will bring the efficiency and speed they need. Engineers figure the cutting-edge software tool technology will make them work faster. After the tools are bought, the milestones are set, the project starts and the limitations of the tools begin to surface. Fixing those limitations becomes a project in itself. This is a source of frustration and agony for project managers and engineers alike.