You can tell your friend that the majority of TT are built to a price point. That means they are built to the level of quality that most customers is are willing to pay for.
If they were all trash and garbage the industry would not sell well over 450,000 units each year for the last five years. Most TTs serve their owners well and those owners keep coming back for the same newer and often bigger units.
If you want more quality and are willing to pay for it, look to Lance, Nash, the Arctic series or the Airstream group. Others such as Casita, Scamp, Bigfoot and other shell types are often rejected because of the cost per size.
If folks really wanted a high quality TT the low volume venders would not be low volume.
The industry builds what the customer will buy. That does include some rather high dollar motor coaches by the way.