I appreciate your effort. Of all the comments, this one is the closest to reality, so I will try to complement it.
The only missing information here is that the narrow band (more sensitive with higher dynamic range) receiver would require more RF filtering centered around the tuned frequency, which is not fine for the broadband receiver. This means you need two actual receivers with separate RF paths and a multiplexer - and this costs more money.
In utopialand, some direct sampling receivers with simple low pass filtering try to get the narrow band performance along with the wide band flavor using a simple DDC. This works very well in the lab with simple tones. In reality, the actual cost is poor IM3 performance with the real signals. It's never a good idea to have a lot of RF gain at a wide open bandwidth.
The higher end, more pragmatic direct sampling receivers address the problem differently. They have very carefully tweaked RF amps and extensive filtering which limits the exposure of the ADC to blockers/interference. Some radios like the NetSDR even notch specific points of the spectrum depending on where you are tuned, just to avoid potential products and/or their harmonics. This also allows them to have a relatively lower usable NF (MDS) without the fear of overloading.
Now the HF+ follows the same design principles, but the technological bricks in use are quite different (More on this later).