When you work, you work on building things that don't have a specific end goal, without a specific deadline, where the success criteria are also not purely academic. To the extent your problem is technical, you may be exploring the cave for a heck of a long time with no light.
You end up fighting with organizational issues as well.
With a bridge, the model tells you about the forces in the structure, the component tolerances, and the likely behaviour under various stressful and extreme conditions.
Same with EE. Commercial board design uses schematic simulation, automated layout, and loading/transient emulation. You can't do modern commercial PC motherboard design without modelling software. (Well - you can. But it'll take far longer and be far less reliable.)
Software dev is more a case of nailing things together until they probably mostly sort-of work.
There's some guild lore - which changes fairly regularly - but no formal modelling. Realistically it's somewhat informed guesswork based on the current lore, mostly tested by trial and error.
I think part of the problem is that most of our "raw materials" like nginx and postgres are so robust that you can build really quite large projects without having to do any modeling or other big planning. Things that have millions of users can still be more-or-less slapped together from default parts.
