However if the airlines post good fares and I plan in advance that should not be a reason to not pamper me once in a while.
But airlines won't upgrade anyone now without reason. And even if they did, they are much more likely to upgrade a "gold" who has paid last minute full Y fare if they need to for operational reasons, rather than a gold who has paid a heavily discounted fare. Some airlines might even upgrade a non-status Full Y ticketholder ahead of their "gold" discount Y traveller.
At the end of the day, it will be for operational reasons only ( overselling or change of aircraft), and the days of upgrading as a way of "thank you" seem to be well and truly gone.