" There's nothing stopping this developer from taking the requirements of the project and developing a solution from the ground-up in their language of choice o

" There's nothing stopping this developer from taking the requirements of the project and developing a solution from the ground-up in their language of choice over the course of a couple weeks. " When I was younger, I would've actually done this. As I got older i learned some things, and one of those things is that 20% of the work will take about 80% of the time. I'm sure he could take a week or two, develop a kick ass demo that demonstrates a working concept... but it won't make the project finish sooner. Rewriting existing code that's hard to work with is essentially defaulting on technical debt. If he skips essential things like writing a proper design doc (documents are a really good way i've learned to communicate with your team, don't skip them!) if he doesn't have good code coverage, then he's simply taking out a new loan.