Different lenses have different uses. Get what suits your requirements and also your wallet.
I use 16-35 II, 24-70 II, 70-200 II and the 100-400 zooms for a large part of my shooting.
The primes 50L, 85L II and 135L are used for extreme wide aperture shooting that is not possible with the zooms - extremely shallow DOF photography / low available light shooting.
The 40mm pancake is used for panoramas and for party shooting where I can hand over the camera to someone else.
The 17mm TS-E is a recent purchase and I'm still learning how to use the TS functions - I plan to use this for indoor architecture and landscape use where I want large DOF without getting hit by diffraction.
Most would say the amount of gear I have as a hobbyist is an overkill - probably so, but hey, it works for me.