Compared to? 6D series are also 1/180. 5D series are 1/200. The smaller curtained APS-C mid & high-range xD & xxD are 1/250.
This was one on the few reasons I didn’t buy the 6D2 when it launched. Shooting in a studio most weeks with my ageing 1D4 at 1/200 for 9 years and then having to drop back down to 1/180.
However, if the price is right at 1299 USD it is good buy, I think. It doesn’t seem long ago since I bought my EOS R I can’t help thinking the RP is a lot better value on launch than the EOS R, but I’m loving my EOS R anyway so guess it doesn’t matter in that case.