i wonder if they'll ever be able to create a human brain in this fashion?
Not soon enough to make it significant.
3D printers are developed by a very small closed community with limited budgets and that won't change for many decades to come - the thing they're used for is personalized one of a kind models and are rarely used even by the people that need them (special fx sculptors, designers of all kinds, etc) as such they are not a commodity.
Most of 3D printers use plastic. Some use metals or glass. But every 3D printer uses ONLY ONE material (not at a time, they generally only can do plastic or metal), hell they can't even do more than one color yet (only one printing head).
Human organs are normally made by more than one type of cells - the brain is made out of 4 for instance. So that's the first (and the much easier to tackle) hurdle - to make a 3D printer which can alternate materials.
The next and much harder problem is resolution, just spraying cells randomly like they do for cartilage won't cut it if they want to copy a brain, they'd need a a printer which can place the cells exactly where they should be. We're not even close to that level of precision.
That being said 3D printers are great. If you want a unique light fixture.