Hair analysis does require samples to compare to, and without a sample to compare another to, it is extremely difficult to come to any conclusion based on hairs.
DNA analysis is not much different, while it is possible to analysis samples and determine if the sample is similar to existing known species, determining the species is difficult, if not impossible, without a sample to compare to.
Hair, DNA, and other sample types might be interesting, but are likely never to be sufficient. A specimen, live or dead, perhaps even individual pieces of a skeleton, such as a skull, are needed to prove the existence.
Unfortunately, in recent times, many people have portrayed hoaxes for no other reason to gain either money, some fame, or both.
Among the scientific community, there are likely many individuals who could lend more assistance into the investigation, but even in science there are 'acceptable subjects' and boxes, and steeping outside of those can quickly lead to a lost of position in their field.
I do not see how the samples can keep coming up inconclusive. Hundreds claim to have hairs, one UM member claims Henner Fahrenbach sent him one in the mail. The Bili Ape was evaluated as a 5th sub species of chimp from one scat sample.
And if the hairs keep coming up "inconclusive" how is that in any way toed to Bigfoot? Inconclusive mean "I do not have a clue" doesn't it? Why are the inconclusive hairs brought up in support of Bigfoot, when they do not actually support anything? Half of them could be Coconut husk fibres for all we know.