The speed and distance that sound travels through water are physics. Y0u said we had the technology to do this easily, so which is it? Do you admit you have no clue as to our technology of the physics which limits it?
How many submarines have collided with undersea objects, assuming this later one qualifies as such? How many billions of dollars do you want to expend to prevent a few accidents that may occur in decades?
I found this article you should read.
A veteran submariner explains the challenges crews face navigating complex undersea environments that they can't even see.
www.thedrive.com
After reading that, you should know that everything I have told you is true.