1) No, universities shouldn't waste too much time preparing people for the job; they should prepare give people the more scientific types of skills that one doesn't really pick up on the job: Data structures, algorithms, paradigms like OOP and FP, etc.
2) Unleashing a horde of yet incompetent newbies on the open source world with a mission to contribute won't be helping FOSS; what's more, if this was the norm, it would cause much more harm than good by spamming projects with low-quality contributions. See Goodharts law.