I think a good example of "Civ Switching" can be found in the Europa Universalis series.
In Europa Universalis, the game begins in 1444 with a large number of civilizations (or "nations") across the world. By the end of the game, many of these will have changed significantly—or disappeared altogether. This dynamic evolution of civilizations happens for a variety of reasons:
1) Elimination through conquest – This is the most straightforward scenario: many civilizations are conquered and removed from the game.
2) Transformation into new civilizations – Some nations can evolve into entirely new entities under specific conditions. For example, a nation with a majority of Italian sub-cultures (es. tuscanian, venetian etc...) between his population that conquers a certain portion of Italy can form the nation of Italy, even though it didn't exist in that time. Similarly, a nomadic Central Asian tribe that takes over much of India can form the Mughal Empire (which instead appeared in the 1444-1821 era, where EU4 takes place). These transitions reflect the emergence of new national identities through conquest, cultural shifts, and political ambition.
3) Emergence of new civilizations – New nations can also arise "from nothing." Every province has the potential to spawn independence movements (under specific conditions, but they can appear anywhere). If rebels take control of enough territory and aren't suppressed, they can declare independence, creating a brand-new nation—or reviving a previously defeated one. Also, with similar but different conditions, in the later stages of the game colonial regions like the Americas frequently see revolutions happen: colonies can rebel and form their own countries, such as the USA, Mexico, or Canada, depending on the territories they control.
While point #1 is a common mechanic in many strategy games, I think Europa Universalis handles points #2 and #3 particularly well. These mechanics bring historical plausibility and dynamic evolution to the gameplay.
Of course, implementing similar features in Civilization would be quite difficult. The fundamental design of Civ differs significantly from Europa Universalis, and replicating these systems would likely require major changes to core mechanics. Still, the Europa Universalis approach could serve as valuable inspiration for designing a meaningful "Civ switching" or "Civ evolution" system in Civ VII.