After my second "flagship" camera was broken at still quite a small shutter count, I lost my trust in the durability of those flagship cameras. My 1D Mark II had a broken shutter after less than 9000 photos. Fortunately it was still under warranty and I did not have to pay for the repair. However the 1D X broke after about 60,000 photos. The PCB had to be replaced and I had to pay more than 600 Euros for the repair. That may not be a lot compared to the price of the camera, but I did not expect that the PCB will brake before that shutter will brake. It is just electronics. I hardly ever used burst mode, as I did not want to waste too many of the expected 400,000 shutter releases. Having a broken camera after 60,000 shots was quite shocking for me. I googled the problem and found out that many people had to replace the PCB of the 1D X after a while. That is not something you should expect from such an expensive camera. Will those problems get even worse with mirrorless cameras, which contain even more electronics and even need electronics just to compose the photo?
As an enthusiast I want to collect my cameras for eternity. They still should work in decades from now, as today decades old cameras still work. Is that no longer the case for modern cameras? Can we expect an R3 to break after five or ten years? That would very much discourage me from paying thousands of Euros for a camera again.