Experimental Methods in RF Design points out that direct conversion
receivers have become highly popular in the past couple of decades... this
seems somewhat surprising; I would have guessed people back in the, e.g.,
'60s, would have gone to great lengths to avoid image reject filters and
long IF chains.

The nice thing about DC IQ receivers (apart from their zero image problem) is
that, any kind of demodulation can be solved in software, and is fully updatable
.... whereas if it's done in hardware, you'd need new hardware for each mode
required etc.

The lack of image problems, simplicity of hardware and fully updatable
modulation schemes is what makes DC IQ so nice -. so it's not surprising to me
at all why it's becoming so popular.

Clive