1440p gaming takes more GPU power to run games than 1080p with 2560x1440 having about 75% more pixels than 1920x1080. My impression, from the average gamer, is that they don't want to spend the extra money on the extra GPU performance and upgrade more frequently. You can really only say that future GPU performance will be greater but demands for 1440p gaming will be greater as well. An entry level or lower midrange GPU bought today will run 1440p games from 4 or 5 years ago fine but a 4 or 5 year old entry level or lower midrange GPU won't run today's games at 1440p very well.
I don't think the average gamer wants to upgrade GPUs fast enough to keep up the performance necessary for 1440p gaming so it may never be as common as 1080p gaming. 1440p gaming is growing though over the years but very slowly. Also look at the direction prices are going with entry level and lower midrange GPUs and it's clear that going to 1440p desktop gaming is a difficult proposition financially for the average PC gamer.
As has already been stated, a poll on an enthusiast site will be skewed in favor of 1440p desktop gaming being more of a serious option. Hell, I've seen for years posters on sites like this saying 4K is going mainstream. That is absurd. 4K desktop gaming will never be more than for a very, very few desktop gamers and certainly never mainstream. The cost of the GPU and the need to upgrade frequently will continue to hold it back in the future just like it always has.
My take on the 1440p proposition won't be popular on an enthusiast site but it is reality from my observations.