Pro-grade cameras (which come their own encumbrances and limitations) simply make it easier to work. Most of the time.
As to Holgas and point-and-shoot cameras not being up to the task, I only have to direct you to the work of David Alan Harvey, Daido Moriyama, David Burnett et al, for proof that it really ain't the camera that holds anyone back, baby.
As to "craft", the craft is primarily in how you frame, expose, place focus, process.... etc. The camera itself provides NO CRAFT WHATSOEVER. The craft is in ordering the visual elements in front of you such that they provide you with an image that is satisfactory to you. That's the photographer's job. If you wish to practice art, then you have to "see" greater relationships and order those elements so that they go deeper than their obvious nature. Again, the camera can't help you with that.
Go look at the Turnley twins' "McClellan Street", completed when they were teenagers. They used a Minolta.
SLRs offer excellent control when it comes to solving the framing and focus/DOF problems. P&S cameras with a live-view screen on the back trace their lineage directly to sheet-film view/field cameras with the bonus of being right-way-up and right-way-round. The small sensor/small lens geometry provides massive DOF which can be very useful. Rangefinders provide other tools for solving the essential problems that the photographer confronts with every image (framing, focus, DOF, exposure) while raising other obstacles.
It doesn't matter which tool you choose; to make good photographs you will still have to solve the problems that are external to the camera and central to the image. Different camera types impose different constraints and the only solution is to either overcome the constraints, integrate them into the process, or choose a camera that makes sense for you to use.
The only way to tell if you need a different camera is to constantly try and solve the external problems while learning how to manipulate your camera without conscious thought. This applies to an M3, a D3, a point-and-shoot and a Holga equally.
The only way to do that is to shoot, select, critique. Shoot, select, repeat.
For many here, the only way to do that is with a small camera that may be integrated into their daily lives.
Keep banging away with the small camera, study visual communications (fine art, journalism, design etc) for those are the vocabularies from which successful photographs are made. They are not made from MTF charts, notions of sharpness, S/N ratios and the like.