No one in the world can tell me an OVF is not superior for sports. Looking through glass is pure and your eyes for days and weeks on end will never stress. Shooting tight fast sports is tough on the eyes period. No EVF can match the speed, agility, clarity of an OVF in all lighting conditions.....anyone who shoots pro sports in these circumstances will understand.
You know the trouble I find when speaking in blanket absolutes? I end up being wrong 100 percent of the time.
Everything you list is your opinion and many, many professionals obviously disagree with you because some of the top pro shooters,
including sports and wildlife photographers, have already moved to mirrorless. I believe the exodus will accelerate as the fresh tech pours into the mirrorless world and DSLR gets left even further behind. I believe we're reaching the point where mirrorless bodies will be able to deliver results that DSLRs just can't match and that gap is going to grow, not shrink. I think that's a statement that everyone can agree with to some degree.
Mirrorless tech is going to advance and DLSR tech is pretty much at a standstill - at least in the Canon world.
I also thought this was interesting to read although it isn't really on-topic for this discussion.
So far, I haven't had a single image where I've looked at my result and said "rolling shutter ruined the shot..." I've had dozens, however, where I've looked at a shot and thought "I'd have never gotten this shot if I wasn't shooting the R5" simply because of the higher FPS. Getting acceptable or 'good' wildlife photos, especially birds, can often be down to the wing position you're able to capture. I'm sure some aspects of sports would be the same. 8FPS out of a 5D4 or 10 FPS out of a 7D2 can't compete with 20FPS out of an R5 - and the R5 does it silently.
Imagine if the 40FPS rumor here is true. Sorry, but once you've shot 20FPS with a completely silent shutter the CLACK-CLACK-CLACK of 10FPS on my 7D2 sounds like a Gatling gun in church - and the critters notice the difference. The regular shutter on my R5 is quieter than the 'silent' shutter on my 5D4, forget the 7D2.
In some sports that obviously doesn't matter, but in many situations (pro golf for example) silent shutter is now preferred around the tee and greens. I'm reading tennis as well. I'm also reading that it's becoming preferred in pre-game and post-game interview rooms as well - just as we've seen in other press events. I can understand why. Not a deal breaker of course but the trend is there and will likely continue rather than recede.
Eventually, unless you're still competitive shooting your ten year old 1DX III, the switch is going to be forced upon you. You'll either switch or you won't be a working photographer anymore because you won't have a mainstream choice.
My bet is that this R1 or whatever it ends up being called is going to be a 20MP monster that opens the door to the remaining DSLR sports and wildlife pros to make the move to mirrorless with all its benefits while still providing the small file size they love for moving things quickly along the wire.
Either way, it is what it is. Saying "no one in the world can tell me an OVF is not superior for sports" is ridiculous. They can express their opinion just as you have expressed yours and it will be just as valid but neither opinion survives as an absolute blanket statement. It's only a 'fact' to the person looking through their choice of viewfinder - whichever viewfinder that may be. At least that's how I see it.
For me, the advantages of mirrorless are beyond reproach. EVF, edge to edge auto-focus, touch and drag, crop-mode, 8K frame grab, best AF system per dollar spent, subject tracking, silent shutter, FPS, resolution - to me, you'd have to be a complete idiot not to see and sieze the advantages. Luckily for everyone that disagrees with me my opinion only has to matter to me. It isn't even remotely fact, it's just my point of view.
BTW - is your screen name based on a motorcycle preference? I'm only asking because I happen to be a GL1800 lover as well.