But what would be the point?
Suppose it is true that Canon aimed to release the R1 in 2021 and called it R3 at a late stage in development. In that case, what will be called the R1? Likely the successor to this camera, right? And that has to be a full development life cycle away, so multiple years.
So Canon would have created a new line, giving people who are buying it the impression that they'll get a mark II version with similar characteristics in 3 to 5 years. And they gave people who won't buy it the impression that the R1 will be coming in the near future - which can't be true if the R1 is what would originally have been called the R1 II. You can't accelerate development of a professional product that has to be fully fleshed out and reliable by that much.
So the name change would lead to Canon eventually disappointing both those who believe the R3 to be the start of a new line, and those who are holding off to buy the R1 once it comes around. In other words, they reduced the number of short to medium term R3 buyers, and set themselves up to screw over the current buyers in the long term. For what benefit? I don't see how changing the name makes any sense.
Also, why is the price lower than the 1DX III? Even if they could have changed the name in response to the A1, could they also have shaved off what is likely over 1000 bucks of the cost? After all, with the other RF equipment launching at higher prices than their EF counterparts, they surely would not have aimed at undercutting the 1DX III price point from the start if the R3 was to be there absolute top end camera.
You are correct.
Adding a few thoughts.
I am willing to entertain the possibility that the R3 might be a one and done model. That's not to buy into the silliness of a name change, but rather suggesting that Canon might be planning to fold the R1 into the regular 1 series replacement cycle, placing an R1 in the mix in 2024. But, they may have recognized that they needed an interim model to compete. So, they may have developed the R3 as a placeholder that can serve the market until they are confident that the technology has advanced to the point where a mirrorless offering can carry the 1 series label without damaging the carefully developed branding.
It's possible that in 2024 they merge the 1D and R3 into a single mirrorless R1 line, just as they did with the 1Dx.
Arguments for this, in my opinion, would be that the R3 does not seem to have held back on anything except dual CFexpress slots. I continue to wonder what an R1 might offer if released in the near term and don't see a lot to differentiate it from the R3. But, if Canon continues to develop the technology, by 2024, an R1 could be loaded with awesome features. If a 2024 R1 is priced $1,000 more than a 2021 R3, I don't think most R3 users would be that upset if a Mark II never materialized.
Other possibility, the R1 will be released in late 2022 early 2023 with a 45mp or higher mp sensor, dual CFexpress slots and a few other tweaks. Basically, the relationship between the R1 and the R3 would be similar to that between the R6 and R5, with a similar price differential. In this case, the R1 moves to a primarily enthusiast camera for consumers with high disposable income and the R3 serves working pros in photojournalism and sports. The market formerly met by the 1D series. I can make some good arguments for this as well, especially since I'm not sure the shrinking professional market can really sustain the 1 series, while the high disposable income enthusiast market certainly can.