The turnaround time for Shuttle was 2-3 months, while building a brand new rocket takes like 1-2 years. Although for the cost of Shuttle, we could have built a whole bunch of expendable rockets, pipelined with a regular launch cadence, and probably also gotten some cost savings through economies of scale.

And, the market projections that indicated there would be enough payloads for large amounts of launches were also basically fraudulent.