Also, of course, without a sound reinforcement system, performers are forced
to learn about dynamics and to learn to control them properly, because there
is nobody else to do it for them.

Of course, there are also performers who choose to work with amplification as
an artistic decision, & who understand & control their dynamics with incredible
precision.
AND they work closely with the sound system engineer to achieve an intended
dynamic result, although dynamics isn't the only, or even necessarily the
predominant element affected by the decision to use amplification.

Scott Fraser