Car manufacturing is a regulated industry. When I buy a car in the USA, even for my taxi business, I shouldn't need to hire a team of engineers to verify that it was properly designed and won't spontaneously combust. I should be able to assume that if the car is being legally sold to the public in the USA, the manufacturer has demonstrated that it meets some basic safety requirements set out by the government. I obviously have some _operational_ responsibilities (e.g. taking my taxis out of service if they're recalled for a design flaw), but I wouldn't consider myself responsible at all if my taxi happened to be the first 2025 Toyota Camry that spontaneously combusted from some design flaw.
Regulators aren't perfect but this is one reason they exist. The FAA has a set of requirements for manufacturing and selling planes in the USA and they have a set of requirements for operating an airline. If I'm operating an airline and the FAA tells me that the verification of an airplane's design and its assembly is the manufacturer's responsibility and not mine, I don't think it's fair to hold me responsible if my brand new airplane falls from the sky because of a design flaw.