I have worked on several but can't go into much detail. One was a big industrial machine with a control software with 7-8 digits lines of code written in assemb

I have worked on several but can't go into much detail. One was a big industrial machine with a control software with 7-8 digits lines of code written in assembly language, some FORTRAN, some Ada, distributed over several processors. Problem was that the manufacturer started in the 70s and never made any attempt to document, rewrite, reengineer the system. Another project with similar characteristics suffered because they were switching tools so fast that they didn't trust them and ended up hoarding all information in the code and never deleted anything. Both projects swallowed millions, had subcontractors that went bankrupt and are still going because without those products the respective companies would go out of business. If you want to make an argument against duct-taping, I'd try to focus on the immediate effects, argue cost/benefit, because in my experience the demise of a project/product can be long of painful (sunken cost fallacy)