Even with good patterns and processes, the shifting landscape of requirements and priorities and business objectives can lead an application into the weeds.
Initially, you may think you're building a single, focused organ like a liver. A few months in you realize that liver needs to power a specialized toaster for English muffins. Eventually, your core offering becomes a conveyor belt that takes toasted rye bread to the buttering rack, and now you need the toaster that only fits two round English muffins per minute to produce 10,000 square pieces of rye per minute while still relying on the liver for power.
Initially, you may think you're building a single, focused organ like a liver. A few months in you realize that liver needs to power a specialized toaster for English muffins. Eventually, your core offering becomes a conveyor belt that takes toasted rye bread to the buttering rack, and now you need the toaster that only fits two round English muffins per minute to produce 10,000 square pieces of rye per minute while still relying on the liver for power.