With pizza delivery you typically (should) tip the driver $5+ ($10+ for larger orders) so idk if that really tracks specifically, but I do largely agree that part of is people being cheap for one reason or another.
I know people who drove for DD and they roughly earn minimum wage ~$15/hr. You can easily deliver 2 orders in an hour. So I don't really buy that either.
I’m not sure I’m understanding your comment exactly so if this response is off let me know: I’m talking about traditional calling pizza in, not app delivery. At least when I was growing up that’s what we typically tipped.