I'd expect the iPhone price hikes to be less even in absolute $ than with the cheap phones. iPhones already had relatively large margins (as a %) for the newly increased costs to partially eat into.
Price go up, demand go down: https://en.wikipedia.org/wiki/Supply_and_demand#/media/File:...
(The iPhone is only a premium brand, not a Veblen good).
Also even if they had pure competitors, demand for high-end smartphones is pretty elastic. People will really just buy fewer phones if they get more expensive.
These announcements have another effect of boosting sales now. Summer is usually a sales slump so selling more now is probably good for Apple.