I’ve done professional setups on most of all the major and sub brands for many, many customers. Some come in with great core instruments as a starting point, and some in states of neglect, and then I’ve had Epiphones and Squiers come in and turn out better than many of their expensive counterparts.
Ive not had a bad ESP come across my bench, nor a USA Jackson, or Schecter. Results may vary, but the main thing is the core instrumen, ie; the body and neck. If the neck isn’t straight and the fingerboard dead flat in truss rod adjustment to start with, the setup quality can diminish significantly from there. I’ve had $3K Gibsons with wavy necks, and I’ve had $300 Squiers with straight necks, and I’ll be honest, much of my repeat business is from making a $300 guitar play like a $3K guitar, but that isn’t always possible if the circumstances aren’t consistent.