you're defining the relative boundaries of 'consistent' subjectively as well. "only consistent player on the team" asserts his consistency relative to other players on the team, and doesnt necessarily equate to this non-definable label of what 'consistency' concretely is
Cy's original statement was that Hayward is consistent, not that he's the most consistent player on the team. The first statement is not undefinable. It means his performances are consistent relative to one another. My impulse, just from watching him play over the years, was to disagree. He's had plenty of ups and downs, and I wouldn't be surprised if he goes on a few games stretche where he's producing well below his averages (specially his shooting) at any point in the season. Upon reflection though, I think that's probably the case with most NBA players, and I probably notice more with Hayward because of his prominent role on the team I watch the most.