See https://developer.mozilla.org/en-US/docs/Web/CSS/font-smooth and https://caniuse.com/font-smooth - no plans to standardize.

macOS devices commonly have Retina screens nowadays; best rendering settings should be decided by the system and/or browser but not by a website.

https://usabilitypost.com/2012/11/05/stop-fixing-font-smoothing/ and https://ui.dev/rwd/articles/font-smoothing and https://github.com/woocommerce/storefront/issues/698 are some opinion pieces (whicht you may disagree with).

Basically: Ship less non-standard, platform-specific, nowadays rather irrelevant stuff in our CSS files to reduce CSS size.