Has Jarre's career sunk? He was touring all over Europe for several consequtive years. That's not sinking. He played in large arenas, not in small backwater clubs or at obscure 80s revival festivals. That would be sinking.
Jarre likes to do unusual things, so maybe after T&T he focused on milking the tours in stead of releasing several new albums and do small tours with each of them. He could just be spreading his projects out and even though he has albums more or less finished, he may think it is smart to release an album when his diary is clean(er).
Jarre has no problem getting his records/music out to the public. He sold 80 million albums, one of the biggest selling artists of all times. His faithful fans would ensure healthy sales even if they dont reach 5 million anymore (music sales has declines everywhere). He IS with AeroProd now, so the only thing he needs is distribution, which is not the same as a "record contract". Distribution is not as risky as a record deal, so it's not as if some big company dont want to sell his records (they sign thousands of acts that sell much less than JMJ).
I think JMJ is too eager to shut up about his work, and wants to signalize he has not retired, and is just waiting for the (for him) right moment.
Some artists need this status to be creative. Some need to be sad. Some need strong feelings in the nature, some need drugs, and some need other "influences" and inspirations. 
