Why did wiring between separate components create a problem for early electronic circuits?

As electronic components like transistors became increasingly miniaturized, the physical size of the individual devices was no longer the primary constraint on circuit dimensions. Instead, the largest and most cumbersome part of an electronic circuit became the awkward, manual wiring required to connect these separate components together.1

This reliance on external wiring made circuits difficult to scale, as complex systems—such as computers—required hundreds of thousands of individual components, making them unrealistically expensive and physically unwieldy to assemble. The development of the integrated circuit solved this problem by eliminating the need for separate wiring; instead, engineers laid thin paths of metal directly onto the same substrate as the electronic devices, effectively "integrating" the entire circuit into a single, compact unit.1