Generally, the more efficient the system, the more fragile it is. I'm not a materials engineer, but metal isn't always the best material for the job. Plus, you can still get built to last appliances if you're willing to shell out as much money as they did in the past. Large appliances used to be major purchases that you had to budget and save up for months to get, but these days you can hop down to the big box store and get a relatively cheap hunk of junk.