I can relate to the OP here. I have bought and sold and bought and sold and owned every L-prime from 14 to 300, and quite a few I have owned several times, same with the zooms. Only I haven't owned because of no interest is the 1635 and the 24-105.
And after ten twelve years of buying, trying and selling I have recently with the purchase of the 200 f2 come to what I feel is pretty much what I want and need, the 2470 mk2 and the 200. I am going to buy the 35 L II, but I have no interest in anything else and I, personally, feel there is nothing I can't shoot the way I like and want with those two(three lenses.
The need for a specific lens might occur later on, but I don't see why it should.
And it's the same with the camera, I have owned all three 5d's and 1d3, 1d4 and now the 1dX and that is the only camera I have been 110% happy with, so I'm not waiting to replace it like I did after trying to track a snail with the early edition 1d3 and failed