There is no reason to suspect that you won't have torrents for things like violins, bikes, or even cars.

This is a common fallacy amongst fans of 3d Printing. I'm a gonna go ahead and call it what it is - Cheez Whiz Engineering.

You list three things. Let's talk about what goes into them.

1) A violin. It's a resonating box with resonators on top. Resonation is a function of density and tensile strength, those densities and tensile strengths being 3-cimensional matrices in tension, 3-dimensional matrices in compression. In order to "make" a violin I need one non-uniform, non-linear material graph for the body. I need another non-uniform, non-linear material graph for the neck. I need another non-linear, non-uniform material graph for the bridge and yet another for the strings. I can build the tuning pegs out of Cheez Whiz, but the sound of a violin is entirely dependent on the resonant properties of those four deep non-linearities.

2) A bicycle. Let's just go to the frame. Suppose I make it out of chrome-moly. This is an anoxic carbon steel blend forged in one atmosphere, tempered in another, joined in another. My fabrication processes are well-understood but they do not lend themselves to thermoplastics. There are parts of a bicycle that lend themselves to Cheez Whiz, but they're the internal guts of the shifters and the Cheez Whiz they lend themselves to is sintered metal powder. Not exactly something user-manipulable on 120W.

3) A car. Let's simplify and go with something stupid simple like "a brake disc." Not the fluid, not the pads, not the bearings, not the studs; those are all deep chemistry and metallurgy. A brake disc is forged in the fires of Hell to do one thing and do it well. It's a multi-tempered multi-pass multi-machined component reliant on many different source materials combined in concert in extreme processing in order to produce one dumb, homogenous part that could be drawn as an STL file by any mook. Make it out of Cheez Whiz, though, and…

Here's the problem with 3d printing. It presumes that all things are made of thermoplastic. Granted - there are things that can be made from thermoplastic. Dice. Watchbands. iPod docks (minus the circuitry). Flowerpots. Amusing 3d Solids. They're lowest-common-denominator strength, though, and usually highest-common-denominator cost. There are very 3d printed things in the world that can't be made radically cheaper via lost wax or injection molding.

So if there's nothing in your life that needs any material strength, you can totally 3d print your entire life. But if you actually need functional goods, you shall remain dependent on the manufacturing apparatus arrayed around you. Yeah, you can 3d-print a bottle opener. it'll cost you 3-4$ in materials. Or, you can go to the store and buy a better bottle opener for 79 cents. They're much easier to stamp out of steel, and they work way better.

That's a bottle opener. You don't want to imagine a Cheez Whiz bicycle.

Yeah, you can print a violin. and if you like listening to Cheez Whiz, that's a bright, bright future.