Those are just the two examples of what is already in civ 7I guess I am presuming all evolutions are available for all civs. I think that has to be the case as there is less to draw from with some civs than others. If every Civ has their own set of bespoke evolutions then sure it would feel less generic, but that feels like a tough ask.
Example 1: Mongol civ unlocked by gameplay
Example 2: Byzantine civ unlocked by Leader/civ*
*this will be DLC eventually
Giving each “civ” or bundle of uniques a gameplay unlock is a good idea because it provides a potential Narrative for the Transition.
If you Don’t have anything that unlocks it (other than a game setting all unlocked) then it’s a little harder to get a good Narrative.