Look at it this way...
When you get involved with a martial art that has a 'known' name, certain assumptions are made. Those assumptions may or may not be correct, right? Just because someone hangs out a shingle and says they teach XYZ style, it doesn't mean that they are good or bad. It's down to the instructor and the student, for the most part.
However, with a 'name' brand, you also get more of an ability to check on things. For example, lineage and the known history of a given instructor.
I like the fact that the style I train in has a 'name' that is recognized, that I belong to a branch of that style that has garnered some respect from serious martial artists over the years, and that my instructor is highly admired and respected in our style. None of that makes him a great teach or me a great student, but they help me to be sure I'm getting excellent training. The rest is up to me, to use my own brain to determine if what I am being taught is real and 'works' or not.
It is certainly possible, as others have said, for a system to be created which is effective and instruction which is high-quality, but which has little in the way of lineage or history. If it works, it works. But there is less there to be investigated ahead of time; a prospective student must take a bigger leap of faith that the training they will get will be effective and 'work'.
When a synthetic history is created that the founder holds out to be factual, and it appears that it may not be factual, although the actual art itself may still be effective, the fact that the story surrounding it was deliberately distorted is kind of a strike against it - at least to me.
"Here is an apple. It was grown in the king's garden and came from a tree that has produced delicious apples for hundreds of years. It is delicious."
Versus
"Here is an apple. I plucked it from a tree I found growing wild in a forest. It is delicious."
Now, either apple may be delicious, right? But I would tend to TRUST the first statement if I had to pick one without tasting first.
If it turns out that the guy making the first statement is lying about where the apple came from, then even if the apple was delicious, I would have less respect for the person who lied to me about it.