I too am amazed at the accuracy of reporting here. I grew up in a "National" home and never knew that it was a prefab. National homes were some of the original post-war prefabs, where walls were delivered and erected on-site. That type of pre-fab is rare now.
I take issue with the "less stringent" HUD code. HUD codes used to be very low, but in Alabama the HUD code is actually stronger than the southern building code, which isn't even enforced in many counties.
You do get what you pay for in modular and manufactured housing, but you also avoid paying for a lot of stuff that is simply waste or overhead in on-site building. We looked at having an on-site cookie cutter home built, and the cost was beyond what we wanted to pay and would have meant a mortgage. By going to high-end manufactured, we upgraded to 6" walls, larger rooms, and a much more workable floor plan. The exact same plan could have been done as a modular, which in retrospect I might have done. Insurance on manufactured housing is higher.
Is the depreciation in a manufactured home a real issue? In some cases, yes. In a lot of others, heck NO! Consider that IF a home appreciates in value - no longer an assured gain and we just saw a post about one that sold for $200,000 a few years back and now sold for $26,000 - that the inflated value means you pay more for taxes and insurance. In addition, the higher price tag means a mortgage. If you have a mortgage, you PRAY for hyperinflation. Otherwise, all the interest you pay is money for nothing.
If you buy manufactured, your value is in the land. Land is a much safer investment than a structure. If you bought a used manufactured home to put on it, you may have paid less than the cost of an automobile. How many automobiles last twenty and thirty years? People think nothing of buying new cars every few years, and think nothing of paying on 30 year mortgages and refinancing to extend the loans. These same people then call buying a manufactured home a poor investment? Uhhhhhh, right.
Cabinets. Our cabinets are fine with one exception - the drawer rails terminate in a cheap plastic support. I had to make ones out of wood and replace those. Faucets - our faucets are nice and work well, but when I had to replace a diverter valve I had to order on the net. Delta is a national standard, and having Banner fixtures is like owning an Amiga back when everyone owned the Apple ][.
Flex ducts. I hate flex ducts. If there is a mouse within a mile, it will find the flex duct and chew holes in it and make a nest.
Manufactured and modular homes give you solid shells that are the basis of a good home. They do so at a price that can't be beat. If you don't put in a dime then they are like any home, they will have problems and look bad. If you spend the money for proper foundations and block wall skirting, and then keep up with maintenance, they are an incredible value.