- iOS and Android: Power-efficient mobile systems, wakelocks, etc.
- Docker, Borg and Kubernetes: Container isolation, cluster orchestrators.
- Modern browser environments, with high degrees of isolation.
- Fast JavaScript runtimes and specialized JITs.
- WASM.
- Ruby and metaprogramming, which rose to considerable commercial success and then petered out. But by the standards of 2000, there's some neat language design there.
- Rust, which successfully applied a lot of lesser-appreciated academic ideas including affine types.
- Type systems retrofitted to many dynamic languages, including Typescript. Typescript is really rather remarkable, even though the types are "unsound", in the technical sense.
Some of these trends were already underway in 2000, when Rob Pike was writing. Admittedly, much of the most important implementation work happened in big tech companies, or occasionally startups. Not in academia. But that's largely a question of scale. Even as early as 1990, it was hard for a professor and a few graduate students to directly change the industry. But plenty of the items on the list above do have roots in academic research.
And Rob Pike did get to write Go. He deliberately ignored quite a bit of interesting research to focus on a specific aesthetic vision, which is fine. And a lot of good systems work has been done in Go.