When an architect is designing a new, novel building does he endure lots of people saying "It'll never get built!"

Yes, and no. Usually somebody else has decided to build a building and the architect's new, novel design has won a bidding process to be that building. Architects may have a few sketches of new, novel buildings on which to base the designs they're going to propose, but architects do not usually go around with a building design looking for somebody to fund its construction. Designing a building is a lot of work; sketches (such as Frank Lloyd Wright's mile high building) are pretty pictures. Designs can run to tens of thousands of pages and take many tens of thousands of hours of labor to produce.

After the architect's proposal wins the bidding process, the real work starts. Architects do not design buildings by themselves! Civil engineers design the structure, mechanical engineers the plumbing and air conditioning systems, fire protection engineers the fire protection systems, electrical engineers do the electrical and lighting design. Every item in that building has to be designed or specified and ordered, with serious penalties for changing one's mind after the order is made. Regulatory agencies have to be satisfied. Builders have to be consulted to make sure that something is possible, or if doing something will require a special, unique, piece of construction equipment that is booked for the next 4 years. (a bridge at the train station in New Haven required a special, near-unique crane to install. Three cranes in the world had the combination of reach and capacity required. The alternative would have required shutting down Amtrak's Northeast Corridor and west-bound commuter rail service out of New Haven for several weeks).

I think one very real difference is that people have been building physical artifacts -- like buildings -- for far longer than we've been building software. Another difference is that the idea of a "dictator programmer" may be alive, but the heroes in engineering are famous for managing projects, not just designing them. Checkout a biography of George Washington Roebling, Kelly Johnson, Isambard Brunel, or even Thomas Edison.