I've been a developer for almost 10 years and during that time, have been involved in small rewrites and major rewrites. None of them have gone well and there w

I've been a developer for almost 10 years and during that time, have been involved in small rewrites and major rewrites. None of them have gone well and there wasn't a single one that we didn't regret starting on. What you think is a mess of legacy code is often less messy than you think and a lot of the odd decisions were often made for very good reasons. When you rewrite a codebase, you often tend to over-engineer it for the vague goals of being "scalable" and "clean" but, while clean on the surface, it often comes out far more complicated and with the a similar number of bugs. Another way to look at it is you're taking what was previously an agile approach of iterative development and replacing it with a waterfall approach which sees a grand end goal (parity with legacy code). Software is complicated and there's no silver bullet. Adopting React over jQuery will not reduce complexity as much as you think. Adopting microservices over a monolith will not reduce complexity as much as you think. The only thing that will ever reduce complexity is careful iterative development of good abstractions which are inserted into the codebase one-at-a-time.