It's a herculean task to create the sort of military industry Russia or US have. Aside from supply chains, there's energy production, factories, workers, engineers that would be needed to spin up such industry. It's a decades long process. Either European leaders have absolutely no clue how modern industry works or they're just cynically lying to European public.

In the 3 years of the war we didn't seen any creation of the military industry in Europe, instead we did seen deindustrialisation in key countries like Germany and UK. Also their so called ally, US, actively supress them with energy prices and actions like Nordstream sabotage. Even the country which military expenditure risen the most, Poland, just buy weapons in Occupied Korea, with barely any effort of sustainability other than forking money. And all that even before we talk about corruption and wastage in governments and military industries.