That is a great article you found, Valisa. It explains nicely at least two common problems.
1. The weak kitten gets too little sugar in the blood. This explains why the common trick to have some -white caro syrup, Dextrose or honey, - on their gum, works so nicely. It is really not a "energy boost" but it is what thay desperately need at this moment. Dextrose (=glucose sugar) is best, but other sugar sources works also.
2. Second, it explains well the factum many had observed: you go with this dying kitten to a vet, vet does examination, gives perhaps a fluid injection, and says, "I dont see anything wrong, he is fine. You can go home with it".... It is NOT grave incompetence, it is simply it is often very difficult to see on a kitten what they are sick from. You see better the cause afterwards, after opening up the body and doing post mortem, there you see the bodyly deficiences, or the inflammation source...
Of course, a really good vet could try with tube feeding, or showed you how to do tube feeding properly. Tube feeing is a very good help in many situations with weak kittens, the problem is it is difficult and very dangerous for a new be... It seems quite a few vets dont themselves know how to do it.
I think I will try to make a thread on this article when I have time. The finds in this here article are too good to drown in an old thread.