Canon will absolutely produce more budget cameras. The RP was just an initial step to lower the cost of entry to FF, and there's still ample room for things to be crippled on that body to push cost lower. Especially once they upgrade their platform to their current or next generation of technology that can share components with the rest of the R lineup.
I also don't think we'll see round sensors though. With the current situation of chip and wafer costs waste is of course an even more important topic, but even under normal circumstances Canon is a Japanese company. I would not be surprised to learn they follow some of the guidance in avoiding waste from lean management.
And with how many actually useful things (RAW histogram, zebras in stills, focus peaking on DSLR, intervalometer in every body, auto exposure linked to spot AF in every body,...) Canon withholds from bodies just because they aren't useful to especially many people, it seems very unlikely that they would add something so niche when it comes with actual costs for each and every body they make, unlike the many software aspects I listed.