If the R3 was meant to be the R3 then they already had started development of the R1 and had developed a product segmentation strategy. They had also built their development and release schedule for the R1 in the context of their plans for other models and lenses.
If the R3 was meant to be the R1 but the renamed it the R3 presumably after seeing the A1, then they have to start development of an R1 when none was planned, juggle all of their resources, including human resources, materials, manufacturing, marketing, etc, decide on a new product segmentation strategy, and then decide how all of this impacts their other planned releases.
So that is a huge difference. Imagine the product planning meetings, the marketing meetings, the engineering meetings, the manufacturing resources and logistics meetings, etc.
It is totally naive to believe that such a name change is trivial. To believe that shows no understanding of what it takes to plan and develop and bring to the market these very sophisticated technology products.
A well run company cannot function that way.