The sentiment that you shouldnt pay rack rate has historically been pretty accurate, but we're in a unique market environment right now. Discounts are fewer right now and are more limited. I don't keep up on discount specifics, but anecdotally I've heard that demand at the Polynesian has been consistently extremely high ever since it reopened from the renovation and therefore discounts there have been very hard to come by. I could be wrong but I think it has been excluded from all of the recent broadly-advertised Disney room rate discounts, including the current promo. Disney is currently now able to highly target their discounts to get occupancy up at resorts that need a bit of a boost.
I'm reserved there in November and I'm unfortunately no longer holding my breath for a discount. Hoping I'll get lucky, but not expecting it.