I browse this website quite often since 2012. I have never seen so many negative comments about Canon these days in comparison with before.
Here's my take:
For many, buying into a dslr system is a major investment you cannot revert w/o losing a lot of €€€ and time to re-learn procedures. And of course there's an emotional attachment to a brand that was in your pocket for all your life. For all this time, people were happy with Canon, keeping lenses longer and changing camera bodies more frequently. Canon made a good transition from film to digital.
But now, with mirrorless arriving and sony having more resources (and probably patents) for sensor research, I feel uneasiness grows if you've bet on the right horse. Canon might very well pull a rabbit out of the hat and surprise us all, but flat out denial that further sensor enhancement (dr or resolution) can be can be beneficial to some is counterproductive: No smoke without fire. Calling people names doesn't help either.
Furthermore, with more cpu power there are more opportunities to harvest this new resource - but Canon seems to be very set upon continuing exactly what they've done for the last decade. So apart from the hardware side, a very conservative software policy results in very stable, working products. But question if this balance won't tip to their disadvantage some time - Magic Lantern won't be around forever for the rescue like with focus peaking, raw histogram and raw video.
Last not least, there's the "value" aspect and the pure competition pressure from Nikon/Sony and 3rd party gear (lenses, flashes). If you are able to afford $15k+ gear, I imagine you're fine with Canon. But seeing what offers are around, you wonder if some rubber rings for weather sealing, a lens hood, ..., shouldn't be a given w/o buying their premium model(s).