That was almost exactly what happened to me a couple of years ago. The company hired a terrible guy with an architect title. What he did was some really simple

That was almost exactly what happened to me a couple of years ago. The company hired a terrible guy with an architect title. What he did was some really simple 3rd party integration sending some transaction details to an accounting provider. Instead of reading from db, he decided to intercept those before saving to db coz some of those were not saved at all (only a problem for accounting, but most of the customers did not use accounting providers anyway). So, he spent over a year on that and moved on to another project. I took the project over and lots of complaints from beta testing customers. My manager and I spoke to him about it and never get anywhere. "Look, I can spend another year on this, and it might never really work. How about let me scrap his sh*t and start over?" I proposed. Months later, green light I got. So I deleted all his code solely for that part, around 5k lines and replaced with merely ~300 lines, never had an issue since then. Soon we hired a new Product Lead, the first thing he did was asking how many lines code we wrote in the past year. Errr, okay, so I pulled out stats from source control. Ouch, it was minus ~3k lines.