The car scenario is good. Ordering a car is not much different than ordering a home to be built. If ordering a car could get me discounts on insurance and tax incentives for efficiency, along with higher resale value, the benefits of ordering a car, would likely outweigh buying an existing car. With houses, we are looking at a slightly different scenario because most existing homes were built prior to 2007 building codes and they many are "used" or in the car business, I believe they would say, "previously owned." A new house should have more value than a similar home built five years ago.
You don't have to hire an architect as many coastal cottage plans are available for less than $1000, including some designs which are built in WaterColor. Many lots do not require a building review committee approval. The biggest difference, in my opinion, is that building today, you would be meeting the newest building codes, which should make for a stronger house than many which were built prior to the 2007 changes in the Codes. Also, in the building boom, building supervisors were spread thinly, and weren't able to keep a close eye on all of the homes being built -- that is one reason why we see so many of those homes with the paint peeling off the trim -- they skipped the primer step. Knowing which types of construction finishes give the largest insurance breaks can also be worked into a new build, giving discounts every month you write the check to the insurance company. Also, there are some discounts given for green building technologies, and that can also reduce monthly expenses. One last advantage I'll mention is that you are getting a new home, which will likely have more resell appeal, and you can build exactly what you want to build, rather than having to choose from the existing inventory.
Sure, there can be advantages to buying existing homes, such as not having to decide on what to build, not having to deal with a contractor whom you don't know (although you will be dealing with a contractor's work if you buy an existing home), you know the final cost (or do you? What will need to be replaced or repaired), and of course the most obvious -- you can move in today.
For someone looking to sit and hold (long term), a lot may be a good choice. It is much less expensive, so you will be better off financially compared to buying a house, if you loose your job or some expensive emergency comes up. Also, you don't have to worry with the expense and hassle of maintenance, nor do you have to worry about utility bills, renters' wear and tear, management fees, higher taxes (compared to a lot), etc. With the lack of interest in lots, I think you can find more growth potential from lots than existing homes, at current prices.