My 2p's worth, for what it is worth. (btw less than 2p like everyone else
). I don't think Canon (or Nikon) have the technology to approach the 1DXII (or D5)performance in mirrorless form atm, nevermind the Sony a9, which is what they would really be up against when it comes to a fast/sport 'Pro' mirrorless. And by then I think Sony will have an a9II, which would be an even harder product to equal/better. Nikon are in the same position, so I think there will be a 1DXIII and a Nikon D6.
What they could do to improve on the 1DXII or D5 to make anyone upgrade is another thing.
That said, Canon and Nikon may have high(er) fps mirrorless cameras before the Olympics, but I can't see many buying to replace what DSLR's they may already have (1DXII, D5, whatever) or the newer DSLR's Canon and Nikon may have brought out pre Olympics, because they will probably just work and can be relied upon where a cutting edge mirrorless, with possibly adapted telephoto lenses, may not be. They could sell to those users who want a fast Canon or Nikon mirrorless in addition, for the features they have over a DSLR, specifically silent shooting, but not instead of in such high pressure environments. No doubt there would be incentives to be seen using such mirrorless cameras though.