Wrong.
When Apple switched to A-series, a new model of iPhone was introduced and a new category (iPad) was released. The switch to A-series helped offset the R&D of a new model. You can see what happened when the iPhone 5 got released, the base price increased.
When Apple saves money in one area, they don't always pocket the difference. They get reinvested elsewhere: iPhone 12's margins are taking a hit despite the lack of inclusion of EarPods and charging brick and smaller shipping volume.
https://9to5mac.com/2020/10/14/ipho...gins-despite-removing-headphones-and-charger/
And if you look at the upcoming MacBook Arm, prices could be lowered:
https://www.tomsguide.com/news/arm-macbook-leak-just-revealed-a-shockingly-low-price
Even reliable leaker Ming Chi Kuo mentions: "The analyst has also suggested in earlier notes that the switch to in-house designs from Intel chips will reduce processor costs by between 40% and 60%, which could lead to a more flexible cost structure and
more competitive product prices."
https://appleinsider.com/articles/20/06/21/arm-based-mac-launch-expected-for-wwdc-says-ming-chi-kuo