What's the difference between " More and more/…er and …er " and the "ever more/ever …er ".
For example.
The tree grew taller and taller.
The tree grow ever taller.
She grew ever more impatient as time passed.
She grew more and more impatient as time passed.

Question

Answer

In answer to your question, "ever more" is mostly confined to the literary language, while "more and more" (or -er and -er) is the  construction we use most of the time in real life.

Answer

'tall' has one syllable, so it is easy to pronounce/say 'taller'.
"Impatient' has (im-pa-ti-ent) has 4 syllables, so it is too hard to pronounce 5 syllables. "impatienter' is too hard to say, and it sounds awful.