I think what has really hurt Canon is their failure so far in the mirrorless segment. As others have said, for quite a while they've relied in large part on high quality glass and people's glass investments within the EF ecosystem to drive people to that and retain them within it. It's worked well - they are "good enough" on the sensor side and have also won (or at least not lost) on things which professionals care about quite a lot like reliability.

But mirrorless eroded a lot of that advantage - they were late to the trend, then came with a substandard offering (EOS M series) and then tried to catch up with the EOS R but leveraging existing glass investments to drive adoption is much harder because people see part of the point of mirrorless as moving to a new mount which allows for smaller lenses (at least at shorter focal lengths).