Re: Needs just a tweak.
"On civil construction / arquitecture[sic], normally, the project is sucessful when the building stands the test of time (aka doesn't fall due to structural flaws)."
The ratio of design/physical construction phases are very different.
The civil engineer/architect team draws up a design & then hands it over to the construction contractor who in turn hands over to the direct labour to the brickies, sparkies, plumbers etc. but a good deal of the detailed design to the host of manufacturing companies who make the bricks, the cement, the screws etc. (and good old nature which has been in the wood making business for millions of years).
In software the physical construction is trivial. The design team is responsible for a much higher proportion of the work. Where pre-built components (libraries) are available the effort needed by the design team in understanding their interfaces is much greater (how complex is the interface of the common house brick?).
There is also a difference in the regulative environment. The building client can't decide that proper lintels, electrical insulation and ventilation aren't needed but nobody will stop the software client deciding to forego proper encryption or sanity checks between the web front-end and the database.