You're right - although there are large gaps in D1 too. High-A compares favorably to the top college conferences for sure (SEC, Pac-12). It's why it would have been a bigger red flag for Benintendi to struggle at Salem, than it was a great sign that he mauled it.
That said, Espinoza doing what he is doing in a full season league as an 18 year old is great, the way it was for Devers. Devers is struggling in Salem, yes - but he is still younger than the first high schooler taken in the most recent draft.