4d8 + cantrip, other spell or even melee attack every turn is still considerably more damage than 1d8+5 per turn, whether they do that for one, two, three, ..., or ten turns. We are comparing damage per turn, the number of turns is irrelevant.

At this point you have yet to make one cogent claim on the subject so I'm going to assume you're trolling on purpose and will not engage you further. Have a good day, sir.