Neither company generally released info about a GPU without it being launched effectively at the same time or within a couple of weeks, this is no different. There has been no change, just people are becoming more ridiculous about it. Nvidia don't give out any information about new gpu's months before launch, or usually even weeks, days, possibly though more often than not the first genuine official real specs are only released at launch by Nvidia, or AMD, or Apple, or like 99% of companies. The only things that usually buck that trend are things that set a platform for years to come, IE cpus and their gpus. General specs, number of cores, socket, chipset features of both AMD and Intel platforms are known 12-18 months in advance because the industry needs to know.
GPU's are plug and play, motherboards/cpus are not, they require the entire industry it shift. You can basically sum it up as devices which are plug and play are generally quite/silent until launch date. Things that plug and play devices actually plug in to, are very widely talked about long before launch for obvious reasons.
When did Nvidia talk about, the crap shield console, or Shield tablet, shield handheld, Titan, Titan Z, Titan X, 980gtx, 680gtx, 580gtx, etc... on launch. When did they start talking about NVlink and what that product would work with... a year ago, because NVlink is platform dependant, the other products were all plug and play.
The very few exceptions are things like the 480gtx, largely because of leaks from a certain someone and because Nvidia screwed it up so badly that it was so late they effectively launched it a couple of times.