After carrying out an orderly retreat from assembly lines as the pandemic arrived in the U.S., many manufacturers pulled out the playbook they followed in past recessions, cutting costs and preserving cash. That left them unprepared for the sharp rebound in consumer demand that began just weeks later and never let up. Without restaurants to visit and trips to take, Americans bought out stocks of cars, boats, appliances, furniture and power tools. Manufacturers have been trying to catch up ever since. Nearly a year since initial coronavirus lockdowns in the U.S., barbells, kitchen mixers, mattresses and webcams are still hard to find. A global shortage of semiconductors has forced many car makers to cut production in recent weeks. Consumer spending on long-lasting goods in the U.S. rose 6.4% last year but domestic production of those goods fell 8.4%, according to federal data, leading to shortages and higher prices.