Fire your most irreplaceable team members now

Although the analysis may be a bit simplistic as there it makes no mention of skill level, I found this really interesting article here:

1. An employee that voluntarily shares his knowledge with his coworkers, keeps nothing solely in his head, but rather strives to document publicly the knowledge and know-how he acquires on the job, is the most precious employee the company has. He knows that if he quits tomorrow, he is totally replaceable, in the sense that there's nothing he would need to teach his replacement - it's all there in the open. No knowledge is permanently lost. This is the guy you never actually want to replace. 
2. An employee that hoards knowledge and positions himself as the omniscient guru, to whom all must come for answers, should be the first one fired. Sometimes people do this unintentionally. They don't see a problem with having all the answers. That's why managers need to instill into them the following mantra: the stuff you keep in your head should only be a copy.

I used to be think of myself as a number 1 type of worker and then I quickly morphed into to a number 2, why? Well, unfortunately management tend to value more a type 2 employee than a type 1, because they are not looking at the medium term, never mind the long term, they just care about the here and now and if somebody can pick up your work, then they can get rid of you. Short sighted? absolutely, but unfortunately this is the world we inhabit.

I'm trying to go back to my good ways of documenting everything and taking an attitude of I cannot afford NOT to document things. I'm not there yet, but I'm getting there. My advise is to try to work for a company where a type 1 worker will not get the sack when push comes to shove.