Plus people have already gotten used to recognizing a domain name simply by having a string of characters followed by .com or one of the other popular TLDs. Trying to keep them from prefixing the domain with www has been a losing battle.
I could see .app taking off though.
Incentive for corporates could be branding marketing. As we know, .com is crowded. Could be easier to push http://aging.beauty into peoples minds than some clever .com variation.
Currently users solve the problem by using Google or Facebook, but that is not in the interest of businesses. They probably would like to see the customers coming directly to then, instead of going through search engine (where user is bombarded with messages from competitors)
Teeth whitening solutions, anyone?
As others have pointed out, we've had things like "travel", "biz", "pro", "me", "mobi", etc for some time now. Not many legit sites operate under these, so I don't really think that these new ones have a big chance. Consumers are already confused about what "www" really is and there is a lot of bad / not-quite-correct / flat-wrong info about what "www" is if you ask even folks who self-identify as "tech savvy".
I sense a lot of consumer confusion coming up, a lot of malware / marketeers using these things, snakeoil SEO firms insisting on them, brands buying up tons because they're scared, and generally a bad time for domains.
Others not so much.