I have been asking my self the very same question!
Over the years, I have been through Nikon, Canon and even ventured into a H2 and a P30+.
Currently I shoot Canon, use 24-70mm L II and 70-200mm L II. Both of these lenses are stellar! For video, I use the Tamron 24-70mm. That lens is the only none-camera maker lens I have ever bought. Very good lens, but the Canon is for sure sharper.
At one point, my kit only contained prime lenses. In general, I found my self often stopping them down to f/2.8, if I did not, I was not happy with the quality. The exception was the above discussed Canon 135mm, very sharp wide open.
For me, shooting with prime lenses is very different to zoom. I think that my time with prime lenses elevated my work ethics. It is like photographing with film, personally, I tend to take more time for composition. You do not have the usual 1.999 card you can delete from, you only have the film.
I am sure that many people have a completely opposite path, going from zoom's into primes. What it all comes down to, a lens is just a tool. What you are comfortable and confident with, you can and will get good results with.