Given the long history of poor quality software devlivered by IC vendors I am reluctant to use any controller with a builtin ROM driver library or vendor code.
These companies are not in the software business. their only goal is to deliver some examples on how to use the chip, not provide production ready, reliable and maintainable code.
As a user of microcontrollers I don't like the idea that every semiconductor vendor rolls his/her own RTOS.
That's IMHO more like a vendor lock in than anything else. Ideally a RTOS should enable you to switch semiconductor manufacturers easily.
BTW I don't think that it will help to throw RTOS solutions to people in order to have more designs going to production. People need also to be trained how to use this kind of technology.