Sustainable industrial transformation is often presented through large system goals: hydrogen, circular economy, waste-to-X, electrification, carbon management, and net-zero manufacturing. In practice, these goals become industrially meaningful only when physical-chemical and thermochemical processes can operate reliably under variable feedstocks, strict emission limits, changing energy prices, product-quality requirements, safety constraints, and real plant integration conditions. This article argues that thermochemical knowledge remains a central enabling competence because it connects feedstock chemistry, reaction pathways, heat and mass transfer, reactor design, gas cleaning, emissions control, product specification, process integration, and scale-up evidence. The article covers combustion, pyrolysis, gasification, reforming, biochar production, syngas generation, hydrogen-related systems, waste valorization, and carbon-management pathways. It proposes a development logic built on problem definition, feedstock-envelope qualification, product-intent design, controlling-phenomena analysis, model-assisted uncertainty reduction, experimental validation, decision-quality piloting, and disciplined scale-up. The central message is that transformation technologies should not be judged by attractive labels or isolated laboratory effects, but by validated operating windows and complete flowsheet consequences. A process is industrially useful only when its benefit remains positive relative to a reference case after energy demand, emissions, separation burden, maintenance, reliability, uncertainty, product specification, and implementation constraints are considered.