I wouldn't call it herd mentality. They're being practical. It's an implementation of best practices. You'll increase conversions if you put things where users

I wouldn't call it herd mentality. They're being practical. It's an implementation of best practices. You'll increase conversions if you put things where users expect them to be. If you build something that differentiates itself at the cost of usability and expectations, you'll most likely hurt your bottom line. Think about cars for a minute. Don't they all look and function the same? Where's the steering wheel? Where's the radio? Where's the motor? Gas pedal? Brake pedal? Seat adjusters? Cup holders? A/C and heat controls? Doors? Most cars are pretty much the same. The differentiation is in the paint colors offered, the design of the body, wheels, and rims. The visual aspects, per se. You see, the same thing could be said for start up sites. Everything is where you expect it to be. What's different are the logos and color schemes used.