Much of esbuild's performance gains are in throwing out a lot of cruft. It definitely benefits from the "fresh rewrite can avoid the cruft of an organic project

Much of esbuild's performance gains are in throwing out a lot of cruft. It definitely benefits from the "fresh rewrite can avoid the cruft of an organic project", including specifically benefiting a lot from ESM as the winning end goal format, and the hindsight of Webpack eventually a massive organic ecosystem of plugins towards a core set of "best practices" over a lot of versions and ecosystem churn. esbuild versus webpack performance is never a fair fight. Most of the other behemoths are still "just" webpack configurations plus bundles of plugins. It will take a while for the build tools in that model to settle down/slim down. (esbuild versus Typescript for "Typescript is the only build tool" workflows is a much more interesting fight. esbuild doesn't do type checking only type stripping so it is also not a fair fight, and you really most often want both, but "type strip-only" modes in Typescript are iterating to compete with esbuild in fun ways, so it is also good for the ecosystem to see the fight happening.) I appreciate esbuild, but I also appreciate esbuild had so much of the benefit of a lot of hindsight and not developing in the open as an ecosystem of plugins like webpack did but rather baking in the known best practices as one core tool.