For most of the history of spaceflight, a rocket was a single-use object. You built an extraordinarily expensive machine, used it once, and watched the bulk of it burn up or sink into the ocean. Imagine scrapping an airliner after one flight and you have the rough economics.
A reusable rocket is built to come back. The most expensive stage flies, returns, lands upright, gets inspected and refuelled, and goes again. The savings are not marginal; reusing the hardware removes the single largest cost from each launch.
This is the unglamorous engine behind almost every "space is booming" headline. Cheaper, repeatable access to orbit is what turns space from a series of rare national events into something closer to an industry with regular traffic.
The effect compounds. As reuse becomes routine and turnaround times shrink, the cost per launch keeps falling, and activities that were once unthinkable on cost grounds — frequent lunar supply runs, for instance — start to look ordinary.
