Consider the source. You asked a manufacturer of artist's acrylics about the longevity of house paint? Last time this came up on WC I contacted a house paint manufacturer. http://www.wetcanvas.com/forums/show...=house+pai nt
If this link works scroll down about 1/4 page to find that post and read to the end. No paint will last forever and artist quality paint, while nice to work with, is commonly over rated.
A mute question really. Almost certainly for us it will not matter what we use. In five hundred years our work won't be in history books or museums. No one will know our names or see our paintings. Will any survive more than a generation or two? Sad, but true...even so I paint.