I did not state in any way, shape or form that my trainer "wear out" my tires. And before we get into a discussion into the opposite end of this point: Of course they will and do 'wear out' if used long enough.
I stated they do cause "some" (as in: A range from minimal and acceptable to melt down stoopid user with rubber shards all over the living room floor) accelerated wear and specified the condition(s) that exacerbate that wear. As a generalization or point of discussion i think most find this to be a true statement.
I did state that slippage and the associated heat causes the tire to wear faster. As can having the roller pressure set too high. Which causes carcass deformation, squirm and...heat in addition to possible damage to the trainer's roller bearings due to excessive radial loading. I have neither condition in either extreme or enough to cause my own results to warrant a dedicated trainer tire or need multiple tires per indoor season.
The disclaimer: My personal results may or may not reflect the experience of others.
My recommendation was the same as yours 'if' a rider encounters unacceptable tire wear: use a sacrificial tire (or buy that dedicated trainer tire if you want to).
My roller is warm to the touch after a session, but not hot. There are no 'black stripes' on my pressure roller. The cheap sew-ups on my track bike do wear, of course, but wear less than if they got outdoor miles on our rough road surface. I call the wear I'm getting on the fluid trainer 'no appreciable' wear or maybe more accurately 'more than acceptable wear'. I won't split hairs on this, but I am plenty satisfied with the tire life I'm getting on my trainer.
The instructions, such as they are, that came with my Kurt Kinetic fluid trainer are somewhat fluid themselves, as far as tire-to-roller pressure goes....telling the user to bring the roller into contact with the tire (which is never perfectly concentric with the axle) and then add 2 to 3 more revolutions of the pressure knob...then add or subtract in quarter to half-turn increments 'if needed' or as required to eliminate evident tire slippage induced by a tug on the wheel using a hand.
Well..duh!
Then, Kinetic offers this: "Do not over-tighten the roller tension knob. Over-tightening will cause both tire and unit damage. Tighten only enough to avoid tire slippage."
Well...double duh!
...and how much is that? I'm being facetious, but only a little. Frankly, knowing how many people have difficulty tying their shoes I am skeptical of the number of users that train with their units with incorrect setups.
I think even a weak rider can out-power a sharp pull of the hand with a standing sprint and do it many times during a hammer session, inducing some slippage.
I've found what works for me by trial and error and offer the caveat YMMV with no tire wear pun intended.
I'm not sure anyone can print out a hard and fast 'rule' on how to set up a trainer as the contact patch size can really vary due to tire pressure, tire size, rubber compound, tread design, etc. And different rubber compounds will, obviously, offer different coefficients of friction and react differently to heat (as will the carcass). General guidelines can be offered, but beyond that...