`import * as` is still treeshakeable and Browsers will do it in-memory as the imports form weak proxies.

Bundlers can treeshake it, it is just harder to do, and so it hasn't always been a priority feature. esbuild especially in the last few years has done a lot of work to treeshake `import * as` in many more scenarios than before. Sure it isn't treeshaking "all" scenarios yet, but it's still getting better.