I work on Positron, and I would say no, it's a different product that has a different set of tradeoffs than RStudio. RStudio is a different IDE, and it is not going anywhere; our company is committed to long term support for it.

I would say that Positron is better for folks who use more than one language (not only R) or want to customize/extend their IDE in a way that is not possible in RStudio.