H1-B transfer is possible if your potential new employer will perform the transfer with USCIS.
(Edit: typo corrected, thanks kaapipo)
(Edit: typo corrected, thanks kaapipo)
I think my main point still stands: you can't always just pack up your things and leave (or rather, you can, but the consequences aren't always a simple job hunt, sometimes they involve relocating internationally) so you may be willing to tolerate more abuse or conditions that are less than perfect for you.