Most apps are trivial for a decent dev to reproduce, I'd wager the root problem is rarely the codebase: the org is rotting. Years of 'fixes' with no progress is like blaming the water for sinking a ship.
Success attracts deadweight who (un)intentionally sandbag efforts to reverse this downward trend for their own self-preservation. I don't blame them, doubt there's a fix when the system requires most people work bullshit jobs instead of collecting UBI.
Bingo. The #1 thing I learned in consulting is that you can't build good software if the processes and structures are wrong in the first place. Ditto with off-the-shelf software.
Something that takes a week in company 1 can take a year in company 2 purely because of organizational issues.
Rotting organizations will produce rotting software.
Success attracts deadweight who (un)intentionally sandbag efforts to reverse this downward trend for their own self-preservation. I don't blame them, doubt there's a fix when the system requires most people work bullshit jobs instead of collecting UBI.