It's anachronistic for Judea in ~30 CE given there was no personal tax, no coins with Ceaser's image on them, and the term 'Ceaser's to refer to the emperor hadn't become a colloquialism to the best of our knowledge.

But had an author of a gospel been writing in, say, Alexandria later on where there was a personal tax and there were coins with Ceaser's image on them and it had become a way of referring to the emperor, you might expect to see that line added in.

Similarly is the emphasis on marriage being between a man and a woman.

Perhaps less socially relevant before Nero married two men while emperor of Rome, which takes place after Jesus was crucified but before most scholars think the first Synoptic gospel was written.

Then on the flip side of the survivorship bias are things that a historical Jesus probably said that aren't in canon, such as saying 81 in the Gospel of Thomas:

Let one who has become wealthy reign, and let one who has power renounce .

Quite relevant to Pilate's reign when Tiberius had inherited being emperor rather than earning it through merit and had abandoned the throne to party on an island for years but didn't hand over the position to anyone else.

Also a line seemingly referred to in 1 Cor 4:8.

And yet it shouldn't quite be surprising that the version of texts decided to be canon right after the emperor of Rome had converted to Christianity doesn't include the pithy line decrying dynastic rule.