When the echoes return from the bottom and are sent from the transducer to the receiver in the form of electrical pulses, they arrive with reduced intensity. It is the responsibility of the receiver to amplify them appropriately.
A sensitive receiver can make a real difference and Lowrance's HDS technology is an example, in fact with a power of only 32W RMS this technology is able to detect a lot of detail at shallow depths, but also to reach high depths with a very low power.
Another benefit of this technology is that you can work with a less powerful transmitter, which therefore also lowers power consumption.
Of course, other houses are also working in the same direction and some promise even more surprising results.