It seems that a Simpsons Movie 2, would most likely happen by the end of the series. They had a similar situation to when Camp Krusty was in development, that occured back at 2015. They held back the release of the episode, "The Man Who Came to Be Dinner"; as they originally had heavily considered the possibility of converting that episode to a proper film sequel.
I am not going to be surprised, that a film is still heavily considered; and that we will eventually see it happen. So yes, it still is alive as it can be; and especially with the show now going over 30 seasons come past 2019.
To put it in perspective, Spongebob's first film was in 2004 and it took them ten year's for them to make a proper film sequel. And it is now only taking only five years for the third sequel to come out.
And, it's now taking about to the length of seven seasons that Hasbro is finally going foward with a film version of their hit TV version of My Little Pony that has captivated male and female demographics of all ages.
The point being, is that you shouldnt underestimate how long things can go, and that it is going to be exciting to see when they eventually go back to doing more Simpsons films, as it will give potentially more motive to expand off the Orlando themed area.