Every news article I've read about this issue points to a new focus by some hotel chains on millenials as the cause for this. Marriott isn't the only one.
Since those of us who are (apparently) curmudgeons prefer desks and don't like to work in the lobby, let's hope that these hotel chains have at least some desks available for us. They could call it the "digitally and socially handicapped" rooms.
As a bit of social commentary, many "millenials" aren't nearly as productive as they think they are. With an almost insane focus on being so constantly digitally connected, they often don't know where their arm ends and their tablet begins. Marriott and some other hotel chains are attempting to take advantage of, and tap into, the "needs" of these people, but in the long run they're just feeding the dragon of reduced productivity and 24-hour Twitteritis. There -- I'm being grumpy. :-)