I look at the trend -- from Civ1 to Civ7 -- of increasing the representation of civs from around the world. While most of the core group of civs from Civ1 and Civ2 were carried forward into Civ6, they added more. More in Civ5 and LOTS more in Civ6. The driving force behind the Civ7 civ choices is to increase visibility for empires and peoples across time and across space/geography. The "blob" civs like India and China, which were comprised of distinctly different leaders and cultures through the centuries have been separated into distinct civs. It's a bold step.
Yes, if Civ7 were to have the same market reception as Beyond Earth, they might consider a change in direction. I expect Civ7 to be more like Civ6, which continues to grow, expand, and add more capabilities. I don't expect them to revert. I expect them to have both expansions and "season passes" as they did in Civ6. Growing the number of choices in each age; expanding the pallette of civ traits, giving us many 3-civ-progressions to make our way to victory.