I think there's a gulf between those who buy equipment and those that
build it.

Those that build use whatever is in the drawer in terms of wire,
connectors, chassis etc. What's important to them is the design,
layout and part selection.

Those that don't live with a bench and a warm soldering iron do
whatever is left for them to do - change cables, tubes, interconnects,
stands and little wooden feet. Because they are equally intelligent
and musical, they create what is within their capacity to create, and
then judge the results. Hence the whole culture of cables, tweaks etc.
I don't see anything wrong with this in moderation, though a lot of
money is being asked for some pretty meaningless stuff.

But in terms of the greatest degree of change you can make to an
existing system, you really have to get inside the chassis. Though
even as I write this I realise that in a digital age, kits and DIY
builds are getting ever more complex. "Maybe not for youngsters who
grew up with digital technology...." I hope to hear from somebody!!!