I agree, brandables are still a premium asset. Just not 95% of the ones listed on BrandBucket. Domain Holdings is an entirely different beast, they have brandables that would sell for low 5-figures at auction alone.
7 years is a long time, and the time is now to buy. But yes, in about 5-7 years domaining will be dead completely; with end users right at the point of auction purchase. So get what you can now and hold on tight.
It's the 'tech-curve' I saw it with eBay when I owned an online cell phone recycling business. I was wildly successful at a time when people were still afraid to use eBay, or didn't understand it; and companies were not buying back phones yet (2004-2007).
Four years later, the market was so flooded that margins became low, and that was a wrap.
I see this happening with domaining in the 5-7 year range.
It also doesn't help that every spamming idiot eMails domain owners and lets them know that a domain they 'could be interested in' will be available shortly and they will get it for you for $250. As the years go on, more of these kind of 'companies' will emerge and premium domain buyers will just go an buy it themselves as soon as they get an eMail like that.
Of course by this time any good 5L.com will all be taken, possibly all combinations, and the excellent domains that we buy now will all be 'premium'.