Software is very much like buildings and road works.
Let's look at the brick-and-mortar world first. We have both architects and engineers. Sometimes there's a separate landscape architect or drainage engineer. We have construction contractors who specialize in high-rise buildings, in stadiums and convention halls, in bridges, or in roads. We have subcontractors for structure, electrical, plumbing, painting, flooring, and heating/air conditioning. Sometimes there are individual contractors for windows and doors, sometimes for data wiring vs. mains, sometimes for landscaping, and sometimes for signage. Then a lot of office furniture, factory equipment, kitchen appliances like walk-in freezers, and such have their own contractors come in.
Then there's the individual family home. There are engineered parts, but the building is almost never engineered. It may not be architected. It's built by a general contractor, sometimes with few to no subcontractors. Oh, there may need to be a master plumber and a master electrician at the company, but they go out to each house a couple of times to supervise the final attachment of things laborers and plumbing/electrical apprentices put in place.
Sometimes a homeowner just wants to pour a new parking pad beside the garage for his boat. So a couple of buddies dig it out, they put up forms, and they haul in some gravel for a base and rent a cement mixer.
Software's much like that. We have big projects that are more or less fully engineered. Sometimes you're building life support. Sometimes you're building a web site to advertise an ice cream truck's schedule and flavors. Often you build something in between life support and the electronic version of a paper flyer (which if you're okay with being static doesn't need programming at all). There are reliability concerns and cost concerns. The thing to do is to get it as reliable as it needs to be within budget. Your little sister's blog doesn't need to fail as gracefully as nuclear power plant controls. Regardless of how important she feels posting about her day is, a town isn't going to be irradiated for three centuries if it's down today.