“The wand chooses the wizard… it’s not always clear why.”
I always imagined that all wands looked roughly the same, maybe slightly different colors, but certainly not all those different, carefully constructed, unique, designs. I think of them as more utilitarian. Though I see the appeal of a unique design for every witch and wizard, it seems impractical, especially since they only cost seven galleons and a unicorn hair can cost up to 10 galleons. It doesn’t seem to be good business for Ollivander.
It’s a fabulous business if he goes and ‘harvests’ all/most of his supplies. Maybe he goes around plucking hairs from unicorns and asking Fawkes for feathers and Charlie Weasley for Dragon heartstrings? Then all he’d have to worry about is getting and forming the wood.