An idea that I fielded some time ago, but did not pursue because
of a lack of support, was that we should encourage homebrewing, not
by a range of disparate kits, but by having a set of standard biscuits,
each with a defined input / output interface such that radios from
the very simple to the very complex could be assembled from
a selection of such biscuits.

eg, an RF amplifier, 50 ohm in and out, 12V supply, agc input
to give a gain range from unity to 20dB, to be used as RF or IF
amplifiers.

Now, it is possible that with the onset of SDR, that such an
approach would be obselescent, but SDR itself is already notorious
for being an off-the-shelf Cheque Book (CB) approach both for
the hardware and also the software.