mixing it up with a troll usually involves descending to it's level, where it beats you with experience
That bit of wisdom actually applies to a flamer and not to a troll and this is an important distinction. As stated, I think that nugget is more likely to encourage people to try to "beat" a troll at some point.
If you "mix it up with a troll", your experience at trolling or flaming makes little difference to the troll. If you win an argument, the troll doesn't care because they were just pretending to take the stance you argued against anyway. Even if they expressed something that they actually believe in, they still don't care because they can just pretend that they didn't believe in it (or pretend they didn't understand your argument or pretend any number of other things to see what reaction they can fake out of you next).
And if you are trying to only respond to a troll's reasonable postings and only in reasonable ways so that they will see how much more rewarding reasonable discourse is, you are likely a fool still. If someone is still trolling, then their reasonable postings are most likely mostly fiction. Rewarding those with reasonable discourse just makes the troll laugh at the fool who believed the pretend tone, encouraging more trolling behavior, giving them one more type of bait to drag around waiting for the next gullible fish.
Yes, given enough time, a troll will either leave or join (where "join" means stop trolling and start participating like a normal person not like a troll). But trying to encourage joining by demonstrating how reasonable discourse works isn't going to work while the person is still in trolling mode. I think that strategy is likely to be about as successful as trying to reform an alcoholic by demonstrating to them how much fun can be had with responsible, social drinking.