The main advantages of mirrorless cameras seem to be the autofocus and the high frame rate, but as I only take photos of architecture, I never had a problem with autofocus and never need more than three frames per second. Having IBIS is nice, but if Canon wanted, they could also put IBIS into a DSLR.
It reminds me of electric cars. People are forced to buy an electric car sooner or later, because car manufacturers will only offer electric cars sooner of later. That does not mean that electric cars are better.