Hm...wild speculation incoming....
1. If the specs are correct, you'll be able to buy an R3 and an R5 and have money left over compared to the price of an R1.
2. As pointed out above, you'd probably have to use an m.2 drive instead of memory cards to match the data rates.
3. Is it possible that we could see an R5s be a 'mini' R1 - same 85mp sensor with much lower FPS and a feature set closer to the R5? If so, no R5S until after 2024. Might fit the 1DXIII/R6 and R3/R6II relationships.
4. I had hoped to have an R1 or 1 series body some day. But seems like it will be out of reach, as I bet they will push the price point on this one to $10k. I could half imagine saving up $6500 for a 1 series, and have been working on it for over 4 years so far. But 10k isn't going to happen. Maybe by the time the R1 hits, the R3 will drop in price, or there will be a stacked sensor R5II that will be more attainable.
Brian