[nickff]

Transistors of the 1950s and 1960s were particularly vulnerable to high voltages. Modern transistors and ICs have some resistance to high voltage discharges such as static electricity, but back in those days, you could easily destroy entire circuits with your hand. Early transistors were made with materials and processes we would consider sub-standard today, which is particularly significant because they were almost exclusively using bipolars instead of MOSFETs (which are much more durable), and the manufacturers of the 60s could not and did not add protection diodes. ESD control was one reason why certain American companies got so far ahead of the Soviets (and the less-adaptable competition such as Phillips, whose workforce refused to adopt ESD control practices).

[yaakov34]

True, and electrostatic discharge from your finger is no joke - it can be tens of kilovolts and carries significant, if not huge, energy. However, a discharge like that going right into a very small device, and the actual die of the transistor is tiny, is very different from interference/EMP damaging said device, where the small size actually offers protection. After all, a completed transistorized device from the 1950s is not vulnerable to static discharge - otherwise, you couldn't pick it up. With everything connected to ground where it should be, it is quite robust.

[nickff]

Modern ICs are much more durable and resistant to ESD than devices from those days; you can run an electronics manufacturing facility (not a semiconductor fab) without much ESD protection these days, whereas that would've been a pipe-dream in the 60s. They are sending consumer and commercial-grade semiconductors into space on satellites with service lives over 12 months these days; back in the 1960s, all satellites required rad-hard components (and had very short service lives). Semiconductors are much better these days, due to improvements in materials, processes, testing, and inspection equipment.