"I would guess that once it's applied, the roof looks new."
It's not so much that the roof "looks" new (remember, if the roof is old, you've been losing the granulation on it as well as flexibility)...
Think of it this way... it's like Lexol for asphalt compounds.
I've seen the analog compound used on roadway asphalt. Does it return the asphalt to as-new condition? No. Does it help extend the asphalt's lifespan by returning some flexibility to it? It seems to.
"I still submit that even if it is physically effective, and lasts the five years that they claim, that in most instances it would be more fiscally effective to throw the thousands of dollars into a new roof."
I'm neither agreeing or disagreeing with that.