Unlikely. They've both said they want to have around 10-year lifespans, and so have some life in them yet. And it seems to be a good bet.
In fact, speaking of bets, I'd like to look into my crystal ball and come up with a few of my own.
My Bet: Sony and Microsoft not only aren't anywhere near done with their hardware designs, they are still working on utter fundamentals of the machines.
Right now, phones are starting to get dual-core processors. Computers with 4 cores are more common, and even some tablets are getting in on that action. A console maker doesn't want to make a console that is going to be outdated almost immediately, but they also want to not have tremendously expensive state-of-the-art parts.
As mentioned in my previous post, telecoms are being asshats and trying to keep us from downloading everything under the sun despite it being increasingly cheap for them to provide us with that. The offshoot of this, especially for Microsoft, is what to do about games. Are they to be download-only? This seems to fit in with the current nickel-and-diming that we see from DLC as of late. If every person or every box that has a game has to have paid for it, then resales (and thus lost money to the publishers) effectively goes to zero. But there might be a backlash from gamers who want to share games with friends, which also would affect the publishers' bottom lines. And we know Gamestop would be devastated if such a thing came to pass.
But, while Microsoft would likely love to make everything download-only, citing faster loading from the lack of moving parts, saving space in the console itself, and cheaper memory as reasons, they are probably wondering about the telecoms right now. Xbox Live is a wonderful thing, but if you have to download gigs and gigs for every game PLUS online gaming's bandwidth above it, people might hit their caps and be displeased, and disinclined to tell their friends and family to buy a console that will cost them more from their ISP.
And conversely, Sony owns Blu-Ray, which Microsoft likely doesn't want to back seeing as they lost a format war to that very format, and their primary competitor in the console wars. Sure, a Blu-Ray has way more storage than a DVD, but if you could just download a game regardless of its size, surely that would be better, right?
It's not a solved issue, I'm nearly certain of it. Physical media are surely going the way of the dinosaur, but I think due to the actions of telecoms in particular, and pressure from gamers and companies like Gamestop to allow resales and sharing, the disk is not going away just yet. Once others like the Amazon Kindle or iPad or other e-readers figure out a system of borrowing and sharing that works well and makes everyone happy, I feel we can transition away from physical media. But until then, we're keeping our discs.
Microsoft and Sony both want their consoles to last another few years, at least. And last they shall. Not just because they want a 10-year cycle, but because they don't know what way to go on even basic hardware specifications yet.