Line Conditioning and possible ground issues?

I get the notion that many power conditioners no matter brand or cost cannot correct and do their intended jobs if for faulty-improper wiring and/or lack of proper ground.  Is this correct?

Mostly.  You cannot/should not fix a wiring problem with a conditioner, that’s for sure as you may ignore life safety issues.  You should not put in a 3 prong outlet if you lack a ground unless that outlet is GFCI protected.  That is allowed. 

You also won’t fix things like bad neutrals, reversed hot to neutral, etc. etc. so if in doubt you 100% should have an electrician check it first.  Also consider an inexpensive outlet tester like this one.  Your N-E should be 2 V or less, and watch it under load (when your system is playing) to make sure your main voltage does not sag and the N-E stays low.  

Having said all of that, if you do not have a true ground, a lot of surge protectors won’t work correctly.  So, if you have a really old home and replace an outlet with a GFCI outlet (totally legal only with GFCI) you'll gain shock protection but most surge protectors you plug into that outlet won’t work correctly.  

Now, if your internal house wiring is solid but you suffer voltage sags due to time of day, seasonal AC use or overall a poor power company it is perfectly acceptable to use a conditioner with voltage regulation.

I understand what you say, thank you for your comments. 

I live in a home built in 1956. Much of the existing circuitry is ungrounded, two wire. We did have a new panel installed and an amperage upgrade, but old wiring still predominates.

Against the advice of some on AG, I plugged my amp into a decent line conditioner/surge protector. The effects of the ungrounded circuitry, which was the feeling of small amounts of current on the metal faceplate, disappeared. 

Not being an expert or trained in electrical circuitry, I would say the line conditioner helped with my major grounding issue.

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I've been doing some research across the web about such.  Some older equipment never had provision for 3 prong cabling with ground.  Perhaps in these cases and if one had an issue with some ground loop hum, you used a cheater plug and the world was right again. 

And that most small kitchen appliances for example cannot have 3 prong plugs.

Of course with a Toaster, where not looking to lessen-squelch line noise like with modern day electronics.