I am thinking this question. Shall we share our knowledge with colleagues?
I think the downside is that if I do that, I will be immediately available in the redundancy list and the boss does not need to care for me any more. The only upside is good for company. The knowledge is not in one single person but in a team.
I think that situation is irrelevant to the market good or bad. But for now it is very hard to find a good job, this becomes more important.