As per the promotional tagline for the set "one last time."
One should not interpret Lucas's words based on a promotional tagline dreamt up by his marketing droids. "One last time" is relative, as we have recently seen. "Your children's children" is absolute (albeit relative to the 1995 cohort). Final video release is also telling; it allowed for future releases on other, yet to be named, formats.
It doesn't seem to me that he's clearly referring to the OOT, it seems he's referring to the prequel trilogy that had been gestating in his beard-- err, brain for years.
Why ever would you assume that? Lucas had made no mention of the PT, or the SE-OT, or any other new or imagined trilogy up to that point in the statement. The whole first paragraph is clearly about the O-OT; it would be very odd for him to start talking about some other trilogy without any other kind of segue.
Again, the gestating prequels.
Note that he said "continually unfolding." Not "will unfold at some point four or five years from now," but "continually." He wasn't trying to sell the public on the PT -- which was barely on the public radar at the time -- but on the continually-published EU novels and comics.
The current version of George Lucas, the film purist, is a relatively recent emanation. During the intertrilogy period, he was George Lucas Who Doesn't Read Everything But Personally Approves Every Story Concept That Goes Through Lucas Licensing and Sometimes Directs Changes to Ensure They Fit In With His Own Ideas. I'm sure there's a quote by Lucy Autrey Wilson or someone like that somewhere in the public record. Anyway, the only aspect of the Star Wars juggernaut that was "continually expanding" in 1995 was the EU.