Do we really need ?

[♔Chello]

@Musical Memories

Compression, limiters and EQ have probably always been used.
There is, however, a certain difference between analogue and digital technology; the latter has (unfortunately) become the standard for compression and limiters.

Most of my best recordings are from the period 1950-1970, which is before the digital age ruined everything.

One of the worst examples of digital use of effects is acoustics (reverb, etc.); modern recordings are taken in completely sound-dead rooms, and (artificial) acoustics are added afterwards.
This is not an ideal way to record, as the best way is ALWAYS to record WITH the natural acoustics, but this places enormous demands on the knowledge of the person doing the recording, and the quality of the equipment used is critical.

The very worst example of digital use is compression (limiters are also a form of compression), and this is widely used for microphones, which destroys the sound effectively and is very audible (to my ears).

I consider EQ the only thing absolutely necessary, because our hearing is 20dB impaired in the lowest and highest frequencies.

Only at a sound pressure of approximately 87.5 dB is our ability to perceive frequencies linear - the frequency curve straightens out, and we do not need loudness at such high sound pressures (limiters).
We rarely play at such high sound pressures, which makes amplification of the lowest and highest frequencies necessary (EQ).

This again means that any EQ will present too high a level at 87.5 dB or more.
I always avoid playing this loud, because our ears start to distort at this level - I always adjust the EQ to work best at 70-80 dB sound pressure.
I therefore regularly use a dB meter when mixing to ensure a reliable result.

The answer to your last question is YES - if you play very loud, because then a straight frequency curve is always the best.

I consistently avoid using compression and limiters, and use reverb and other acoustic DSP as well as EQ with great care.