I understand the main points of your post and agree that PS is seldom practical as it routinely selects the most expensive product as the best although the writeup says the budget buy is fully functional (which to me is the definition of practical).
In this case tho' I think you might have missed the point. What PS reports is that the ABYC standard does not mandate tinned wire, and to quote 'the un-tinned wire has been used for years and provides more than adequate service life in most cases'
In THIS case they were, IMHO, being practical - it was not cost or functionally practical to rewire an entire boat simply because it was not wired with tinned wire. - Workman ship was good and the connections were anchor crimps with heat sealed ends.
This is in response to a guy asking if he should rip all the wire out of his boat even tho it was serviceable and of the right grade.
The jacket of your wire is perhaps not the only issue, based on it's location it was routinely submerged and therefore should have been a better grade and tinned, I also doubt the ends were sealed.
I've never had a problem using heat shrink as they suggest, but I've got a lot of training doing just that in the Navy as a electronics repairman (submarine Radioman) and a Metals Processing Specialist (welder, solder, braze etc) in the Air Force.
My 86 Hunter 31 did not use tinned wires and not one had a corrosion problem at 20 years old. I know because I checked the heck out of it - mind you not one was heat shrink sealed either - not even the bilge pump wiring.
Sealed, good jacketed, normal wires that don't see water intrusion are absolutely fine and good for 20 years - to me that is practical. At 20 years one expects to upgrade/replace things on a boat.