Earlier quoted context omitted.
Apple hasn’t had any plastic devices for some time now.
I'm referring to the 2010 polycarbonate one here: https://everymac.com/systems/apple/macbook/specs/macbook-cor... Not sure why my initial comment is -4 votes right now. What am I remembering wrong?
"MacBook" (not Pro) was plastic from the start, and introduced the same year as the MacBook Pro (always aluminum): 2006. The plastic MacBook was discontinued after the 2010 model. There was a one-off aluminum 13" MacBook in 2008, but it coexisted with the plastic MacBook and was not replaced by a plastic model—instead, the 13" model was promoted up to the MacBook Pro product line, which previously had been just 15" and 17".
After several years of not having a plain MacBook, Apple did the 12" aluminum MacBook from 2015 to 2017. It was basically what they wished the MacBook Air could be, but was too expensive and too thermally constrained to truly replace the MacBook Air of the time. It was killed when they finally upgraded the MacBook Air to have a Retina display.