This seems like color commentary that isn't supported by their sources, or data. I'm not sure how they are supporting this statement. Apple's recent quarterly earnings [0] showed iPhone sales as (essentially) stable, year over year. ASP increased to $800 dollars (!) which would point to the iPhone X doing relatively well, despite not being available for the entire quarter.
Even beyond that, there is no way for Apple to begin product development at a point after they saw the Q4 results. There is far to much lead-time required for them to be able to wait until now to do so.
My guess is that 1) the rumors of these 2 new models are true, 2) Apple committed to this product roadmap a long time ago, and 3) Bloomberg is adding it's own spin to make the leaks more salacious.
[0] - https://sixcolors.com/post/2018/02/apple-reports-its-holiday...