Forgive my ignorance but which machines depend almost entirely on quantum principles?
Google or ask an LLM about the technological application of solid state physics or many body quantum physics.
The processor of the computer you are writing your question on is using tunnelling transistors.
Modern processors are designed to minimise quantum effects, because phenomena like tunnelling create inefficient leakage currents.
All the idea of valence and conduction bands depends on quantum effects. The holes are quantum effects, the electrons are not plain electrons and in particular they have an effective mass that is not equal to the mass of a plain electron traveling in vacuum.
Anyway, I prefer LEDs as an example.
When you ask what time it is, the answer ultimately comes from an atomic clock that uses quantum state selection. You could argue that any sort of fluorescent lamp or LED is quantum-driven, based on bandgap thresholds or ionization of gas. Same for anything involving solar PV electricity generation.
The example the author gives, transistors that somehow rely on quantum tunneling to produce gain, is not a good example at all. In fact it's downright wrong. The essay could have been titled "I don't understand transistors."