I understand your sentiments. The trend of making rigs very small can also
make them more
difficult to use. As an example of a rig that is more compact than most
commercial off-the-shelf
ones, look at the Elecraft range. I love the performance of my K2.
However, the front panel size
means that each key is often performing at least 2 different functions,
sometimes 3. Many on the
Elecraft reflector have expressed a desire for a larger FP when more
functions could be available
by dedicated buttons. So I think that ergonomics comes into play. For even
higher component
density, again mostly with discrete components, look at the KX1. A fun cw
qrp tcvr to build. So
it's not always the case that HB rigs have to be very much larger than
commercial rigs.
=============================
A example of good ergonomics are the Watkins & Johnson commercial receivers
, in a 19 inch enclosure with a large functional front panel. Inside a tiny
switch mode power supply and a few small PCB modules ; the box being about
half empty .

Same with my old TenTec Paragon transceiver ,a large enclosure with
ergonomical FP and separate cable linked modules inside.
Also for homebrew equipment using a relatively large enclosure ,you have a
large FP and oodles of space to fit separate screened modules which can be
individually tested (building block method). The RF modules based on 50Ohms
IN and 50Ohms OUT can be readily interconnected with ready made short coax
leads with SMA or similar connectors . These links can be found at flea
markets , probably surplus leftovers from the mobile phone industry.

Frank GM0CSZ / KN6WH