They'll cut it. It's the old model.
I would be surprised if it was ever upgraded again. Theres just no point.
They may keep it around as a cheap alternative for a few years, like the ipod classic, but the MBP never made a dramatic change like the ipod did...the new ones look like the old ones, and the main difference in ipods was going from 160gb to something like 16 or 32gb, losing where you put most of your music in a music player..meanwhile, there is no single giant obvious drawback to the rMBP. So cMBP won't be around too long.It will be like the plastic MB and the MBA cycle. Once retina's drop a little in price, the cMBP will be gone.
It's been very clear for years now that Apples line up is heading towards: wireless, minimal cables, thin, light, power through integration of software and components, sealed units, and all retina.
The cMBP is not aimed towards those things. It's advantage is upgradeability (and price), something Apple doesn't prioritize or is moving away from because it makes products thicker, with more parts and less room for useful stuff while a relatively small number truly require accessibility.
Apple has a vision and is moving to make it a reality, and they are banking people will like it even if it is new and different than what they are used to. Just like they always have; they released the cube, the Mac, the iMac, the new MacPro, the iPhone, the iPod, TB, MBA etc etc.
You want your laptop to last more than 3 years? Then....use it for more than 3 years. This isn't 1997, or even 2005, where your computer can barely run an OS 2-4 years later. Its going to last at least 5 or 6 if you want, more for basic tasks. If you are doing advanced tasks, well, you could never upgrade the GPU or CPU anyways on a laptop, which is the main reason to upgrade. So your cycle hasn't changed.
Expandability in a laptop is, and always has been, not useful (thats why few do it). You can't upgrade the processor or the graphics card without major work, and never have been able to. People don't use multiple batteries enough to make it worth having a smaller, swappable battery. The only thing is the HD and the RAM. People I know buy laptops because their old one is "slow", not because they ran out of space on the HD. The only useful upgrade is RAM.
4gb of RAM has been workable for years now; I have 4gb and still run Aperture fine. 8gb will run basic apps for many, many years. 8gb will run prosumer apps for at least 3-4 years, and pro apps for less depending on what you are doing. 16gb should serve demanding users for a long time, YMMV depending on what you are doing. But I imagine if you REALLY NEED more than that much, you work on a desktop or at an office. I can't think of people who do 3d modeling, high level photoshop, atmosphere simulations etc etc in their hotel room/coffee shop.
HD space? Get the 512 and store everything else on a drive or in the cloud. Its 2013, people and industry are moving away from gigantic amounts of files needed on board at all times. If you are a pro who needs 1.5 tb with you to edit movies on location, use an external. Now your project works on a desktop too, and if its USB3, theres no loss to using an external connection. A 2tb HDD is a little bigger than an iphone.
I am sure someone will reply in anger, but I don't mean to offend or tell anyone what to do. I am just pointing out the way Apple and most of the world is moving, which is away from the cMBP. If any of the cMBP fans could really explain (cogently please) any upgrades that make a cMBP computer last longer or really improve it, I would be honestly glad to hear it....personally, I plan on spending some $500 and not worrying about a onetime upgrade in 3 years thats going to save me $200.