It's possible to consider Bouch 'unlucky' as the Tay Bridge fell over when a gale pressed on a train crossing it.
That and it was badly designed, badly built and even more badly maintained... But you're right, if it had collapsed without the significant loss of life, it would probably have been a case of "stick the missing bit back on", bolt on a few reinforcing bits of iron and carry on with operations and consider it a lesson to be learned in the next bridge.
After just re-reading the Lighthouse Stevensons, demonstrates your point about the lack of formal education of many contemporary engineers. Robert S was more fortunate in his assumptions than Thomas B. Of course most people don't remember the hundreds of bridges Bouch built that are still standing. The spectacular (if a bit more diminutive) Bilston Viaduct in our own back yard.
Even in the late 20th C. with hindsight and computers
And classic case of the Hyatt Regency Skywalk collapse.