Pneumatic valves are expensive. They have been used in F1. Similarly, despite overhead 𝚟̶𝚊̶𝚕̶𝚟̶𝚎̶𝚜̶ cams being invented in 1902, they weren’t popularized until the 1983 Toyota Corolla, and you can still find pushrods in the 2020 Corvette.
Seems you misspoke. We've been using overhead valves far longer than 1983. Overhead cam is probably what you meant. Though depending on how mainstream it needs to be in order to be considered 'popular', the first dual overhead cam engine was in production in the 20s, IIRC.
