One of my biggest pet peeves in software development is the compulsion that so many developers have to rip up the foundation and completely build something over again, pretty much from scratch.
I’ve been that developer plenty of times. It’s easy to walk in, see that there are some problems, and want to raze everything. Sometimes that’s a reasonable answer, but every apparent mismatch or hack was put in to solve a particular business rule, many of which are lost to the mists of time. Burning down and starting over loses a lot of that information, so rebuilding is something you do with caution.