I personally think you’re nitpicking a bit unfairly here. Frontiers “released” for PC from May this year and “releases” bit by bit bi-monthly until something like Q1 next year. Did you really expect them to do that concurrently with iOS? (And android).
Is Rise and Fall, Gathering Storm, and all the other Civs packs not enough to hold you out until they release Frontiers on iOS?
There are not many games at all that have concurrent releases with the PC counterparts. And PC often forms the platform of choice for testing and release and bug squashing rather than ending up with a mess all at once on all platforms.
Who even says rise and fall and gathering storm isn’t “the full experience”. Just because there’s currently a bi-monthly release of some more stuff which you don’t at all need, doesn’t mean rise and fall and gathering storm doesn’t give you “the full experience”. They’re pretty great expansions, and they were the full experience on PC for years.