If my taxi goes to where I want to go, doesn't take a silly detour for money, and doesn't physically assault me, I'm good.
Outside of that, who cares, really? Where and who are these princesses that really care if their cab driver is a 4.2 or 4.6?
I tend to rate basically everyone in service interactions 5 stars because the fact they even turn up to their minimum wage job is a colossal privilege for me to enjoy.
Like, would you rate your bus driver if you could? Your checkout operator? Why? What possible benefit do you derive from that to outweigh the embarassment (to _both_ parties)?