[boxy_brown]

You are missing an important point: different systems fail in very different ways. The reason why people will generally prefer software over other ways of building things is because the cost of failure is often very low. No one is going to die if a website serves an incorrect image, nor will such a bug require billions of dollars worth of semiconductor inventory to be recalled to repair.

If every software project was run like an avionics project, software would be more reliable and of higher quality. But the world would be worse off; most of the software people use would never come into existence.

[Jtsummers]

I don't think I'm missing the point, I'm not calling for photoshop plugin devs to have the same requirements as others, I'm saying I wouldn't object to licensure for software devs on many categories of systems: medical and avionics are two obvious categories. Perhaps I should have stated that more clearly, but I figured most people would get that a browser-based game is in a totally different league than the software controlling acceleration in your vehicle.

[sgt101]

Sometimes this is true, but it misses some things.

Sometimes the cost of failure appears low, but is actually massive because the failure mode is not understood. For example a spreadsheet that miscalculates and causes a bad investment decision and a corporate failure.

Software is often chosen because it trades off against weight (in physical systems) or people (more commonly).

Software is fundamentally different because it is not commonly toleranced or the tolerancing of software is not understood. Reliability in physical engineering is understood in terms of the limits to which a component can be pushed. This concept seems not to be applicable to software.