Jarre recreated Oxygene a few years ago because he could not get access to his original master tapes which are the property of his old record label, he and three men of his team played the original Oxygene note for note on the original equipment, this became Oxygene : New Master Recording, he also performed 10 concerts playing tracks from Oxygene and other albums and some new tracks on only vintage equipment, there's a DVD of that called Oxygene: Live In Your Living Room which holds one concert and a lot of extra stuff including Jarre demonstrating some of his instruments like the Eminent 310U, Memory Moog, ARP 2600 etc.
As for why Jarre doesn't continue with Equinoxe, I have no idea, maybe it is because the mood on Equinoxe is different, also, Oxygene was unique when it came out, Equinoxe is just as timeless and maybe in some ways even better than Oxygene but it wasn't new or groundbreaking.
But who knows, maybe all the sudden Equinoxe 2 will appear in 2017.
Also a tip, Electronica I and II, I can highly recommend them, they contain very diverse music.