In the retail and small/medium business market the reality is that Dell, HP, and the like are under so much pressure to cut margins that they'll go with whoever is cheapest, and customers almost never escalate things to tort.
Dell PC power supplies are made for them by someone else, proprietary in size and connector, and gosh, wouldn't you know it - they have a pretty high failure rate. They last just long enough to make it out of the warranty period, and then they make for a really nice revenue stream for Dell via replacement PSUs or pushing the customer to buy a new system entirely.
Even failure within the warranty period is acceptable in the consumer market because integrators have it down to a science exhausting people on the customer support side. Long phone queue times, incompetent support agents who have to transfer you to different agents and likely drop the call entirely, silly policies like requiring a reformat/OS reinstall for everything, and so on.