True, but it also depend on the student! I am of a particular complexity where mentors would simply give up, because I would anyways in time find my own path and not listen to sage advices - but I do pocket them all in my conscious subconscious, and do consider. Although do not have the capacity to try them all out!
Mentors/gurus are essential in life for meaningful progress. But we all have differences in how we function as teacher and student, so it is very non-linear what results come to be and how.
Regarding mentorship, it's more of a happening, than something that can be manufactured. Meaning in a deep mentoring relationship, there are qualities hard to replicate. So yes, while you can and should seek, there's no guarantees involved in any way how it'll turn out. What we hear of success stories and anecdotes, are hindsight and selection biased. Also please consider the fact that a mentoring relationship can be time-bound, it'll always have a definite ending, though we may or may not choose how that ending should be.
Beggars make poor students though.
Best bet would be to ask yourself: How do I function as mentor, and how can I progress in my mentoring? When you give, so shall you receive...