On the basic component end, the history of early electronics was a search for gain. Modern components have so much gain you can throw much of it away to make digital switches or negative feedback amplifiers. Early electronics struggled to get enough gain to drive headphones. Lack of good amplifiers limited the range of long distance telephones.
There's a whole history of forgotten attempts to get some gain. Edison's electromotograph. (See if you can find out how that works. Edison discovered variable friction depending on electric current, but the physics wasn't understood until the 1960s or so.) A speaker driver pushing against a carbon microphone (early Bell System long distance). Higher power devices included magnetic amplifiers (the UNIVAC Solid State computer used those) and large Ward-Leonard drives, used for elevator control for many decades.
There was a long struggle on the transmit side of radio to get gain at high power. The Alexanderson alternator, a high frequency AC generator, was the first real success. There's a long history of transmitting tubes, finally maxing out in radar systems for the DEW line that had tubes with their own vacuum pumps.
Another kludge was the super-regenerative receiver, where positive feedback was used to run the same signal through the same stage more repeatedly. Noted for producing loud squealing sounds.
There's also some history on the musical side. Look up the Teleharmonium, a musical instrument the size of a building. One was actually built. Lacking an amp, they had a sizable AC generator for each note. There's also the switchgear used in large pipe organs, with both electrical and pneumatic components. Those were workarounds for not having enough gain.
We're spoiled today. You can hold the semiconductors used for controlling a locomotive's power in your hand. The first half of the 20th century, though, was a struggle to get enough gain to get anything done.