I guess I could have been a bit more clear on the "inspect wire" part.....
What we're looking for, along with cuts and abrasions, is "lightning
strikes" - some of these are very obvious, some aren't. Using a scope is no
guaranty of finding faulty insulation. At idle, required voltage (the
pressure required to ionize the spark plug gap) is much less than required
voltage at a wide open throttle romp. The first gap to ionize will be the
gap requiring the least voltage. At idle, this may be the spark plug gap -
under load, it may be an "unauthorized" gap somewhere else in the system.

A "poor mans" insulation test is to have someone perform a brief stall test
on a dark night while watching the engine compartment (disable the underhood
lamp, first). Bear in mind that there are no transmissions that enjoy stall
testing. The heat built in the torque converter is astounding...... Any
stall test should be followed by a couple of minutes of high idle in neutral
to remove heat from the converter.

Jumping into the wayback machine with Prof Peabody (if you can remember
that, you're in trouble), we return to my youth. First I must point out that
we are talking breaker point ignition, here, and available voltage was much
lower than what we see now. We took a 100 foot roll of bulk spark plug wire
and ran it out to the parking lot and back leaving several feet between the
two lays to avoid any EMF induced activity. The wire was the usual Hypalon
insulated, carbon impregnated cotton core wire that we used then. Good
quality connectors and boots were installed at the distributor cap and plug.
I can't recall what we measured with an ohm-meter (other than we did indeed
have continuity), but the scope pattern looked exactly like the other
cylinders in the motor. Bear in mind that a resistance indicates some kind
of continuity where a gap is a gap and no resistance can be implied.

Without specialized equipment, we are reduced to other methods. Admittedly,
some of these methods aren't as good as what's available but they suffice.
Some of the testing available isn't going to mean much to most observers
without specialized training (good ol' Catch 22). We have to remember that
there are those coming to the NG because they are cash strapped and shop
time can mean the difference between Kraft dinner and hamburger. Others are
trying to save money now in order to prepare for their golden years. For
whatever reason..... I can't see overspending on a repair nor can I
understand underspending on a repair.(what with the chance of repeat
failure).

I realize that many don't have experience in my area of expertise (but I'm
smart enough to know that they have expertise that I can only dream of in
other areas) and I try to keep stuff simple. One big problem involves those
actions that have become "unconscious"..... I do them without thinking about
them and forget to tell people that I do them.... I document everything on
the back of my RO..... if I don't think real hard, I can "perform" the
diagnosis and repair in a half-dozen lines of text. If I itemize every
operation, I can produce reams of paper....