Why do so many people have problems with bass?

Bass takes the most energy and it is whre problems will show first.

What is so challenging for systems to produce quality bass?

The room!

the room…. bass is big wavelength energy in a relatively small space. Wave cancellation and reinforcement…happens… I get great bass in a variety of rooms using Vandersteen high pass filters and his innovative subwoofers ( some built into the main speakers ) with 11 bands of analog EQ below 120 HZ.  

Enjoy the music ;-)

Jim

What hertz range we talking about?

Lowest note on a bass guitar is 41 Hz and a Piano 27Hz. High C on a piano is ~4KHz.

A lot of the music we hear is really in the midrange, so a set up with great midrange will give plenty of thump.

Low or sub bass is really the energy / power we feel in the music and in a confined space, sometimes less is more. 

OP, have you heard a system and room with really good bass? If not, you might not know what you're missing.