Glad you're having fun, but I don't think your samples of niche scents are representative. Tom Ford and Chanel I have difficulty accepting as being niche.
After I went through a similar immersion, I was shocked at how poor their longevity was compared to regular designer scents, not to mention the paucity of sillage. (Niche were about three quarters duds in the longevity department, compared to designer, which were about a quarter duds).
Since that time, I've found that Serge Lutens, MPG and L.T.Piver are generally a lot better in the longevity department than many other niche scents. And the Tom Ford ones I've tested had very good longevity too.
Also, a lot of the novelty of various niche offerings to first timers is their rawer, less refined components relative to the recent generations of highly refined designers scents. But if they had tried designer scents like Aqua di Selva or many of the Caron ones as I had, they wouldn't have seemed so novel.
Where many of the niche scents are indeed novel, is the way they mix together components typically associated with masculine and feminine scents, and call them unisex. This is in sharp contrast to designer unisex scents which tend to shy away from using strongly masculine or feminine components.
As you seem to value longevity and sillage, I'll be interested to see if you remain as enthused after you've properly tested more samples from different niche houses.