Language popularity is cyclical; the hedge is to treat Rust as an implementation detail behind stable, language-agnostic boundaries (protocols, C ABI, WASM) and invest in strong tests/specs. If Rust wanes, migrate piecemeal: keep interfaces, reimplement modules elsewhere, and verify parity with property tests and benchmarks. Multi-agent, agentic LLM workflows can prototype alternatives in parallel, generate FFI/interop shims, and cross-check behavior to de-risk the swap without another “big rewrite.”