Mono Blocks / why are they not more prevalent? + Wyrded4Sound SX1000R

One advantage to using monoblocks is locating each monoblock close to each speaker thus yielding a very short speaker cable. With that said I agree that a lot of audiophiles don't hear the difference between a stereo amp vs the same amp in monoblock form.

If you notice that most mono block makers also make a stereo version that’s cheaper. I am really happy with my BHK 300 mono blocks, but I have wondered if I’d be able to hear the difference between the stereo version and the mono blocks.

I also like tube monoblock amps.   I am currently running two McIntosh Mc275 amps in monoblock mode.  I believe you get more dynamic headroom, more current, better handling of low impedance drops of specific speakers (like my Wilson Watt Puppy 8).  Crosstalk is also nonexistant.  

Personally, I think the advantage of monoblocks are mostly effected by the architecture of the amps, the type of speakers you choose to use, and the size of the room. So, in my case, a large room, and tube amps with Speakers that dip to low impedance at specific frequencies is a good use case for monoblock tube amps.  So, in the right use case, I do believe you get better sound than the same monoblock amp in stereo mode. 

Seven of my last eight amplifiers have been monoblocks.  With their dedicated (not shared) power supply, monoblocks typically offer the advantages of superior channel separation without crosstalk, improved soundstaging, absence of inter-channel modulation, and increased dynamic headroom.  They also facilitate the use of short speaker cables, at the expense of longer ICs and PCs.  However, monoblocks using a bridged load design can be noiser and are certainly less effective (or even problematic) when driving low impedance speakers.

To your question, I have found monoblocks to be quite prevalent although the move to more compact systems (by some) would certainly benefit by the use of stereo amplifiers.  In addition, all things being somewhat equal, stereo amplifiers are less expensive (per watt of power) due to the absence of redundancy of expensive parts such as transformers and metal chassis.  Therefore, they may be an easier product for manufacturers to move.

@emergingsoul - I respectfully disagree that 'nobody likes to live in an apartment because of the noise'. I've lived in an apartment for 35 years and quite enjoy it, and there's a lot less unwanted noise between floors (in my case, none, unless nobody but quiet, non-vocal people who don't listen to music or watch TV have lived above or below me for 35 years) with a foot of concrete separating them than in any house I've lived in.