Also, I think the author missed the real point. They have a shop where designs are done in caffeinated weekend pushes without input from other developers. This sounds like a shop full of junior developers. Engineering is not just about code. It is the balance of creation with constraints. They could have know the "old-new" system wouldn't have worked if they had some idea of load, or were measuring latency. They could have used these measurements to push a better design if they bothered with a design process. People would have supported the design, and slogged through bugs if people were bought into it actually be the correct design. Instead, we had a system written twice.
There's a reason senior engineers are paid what they're paid, and it's because it saves time like this. You pay a senior engineer because they sidestep these problems.