Except that it's still possible to damage stuff in many of these systems, if you make a bad connection. But at the same time, they don't have the flexibility and power of a full "You're on your own" system.

What if I want battery power and need 12v? Well, the modular interface generally defines 4 pins, GND, 5v or 3.3v, and two data pins, there's no standard for anything more, it has to happen outside the modular system.

There's no commercial products made with these standards either, it wouldn't really make that much sense, only a small part of the product can be done modular-ly.

Real modularity is possible, look at production backplane based systems.

Commercial products, at least big stuff like appliances, are totally possible with a modular system, just not with one tiny connector for everything.

In the old days, we had breadboards, the original modular system. You'd plug together chips and discrete parts, and eventually you could make a PCB for a permanent version.

It's very cheap to mass produce SMD parts. Who needs an idiot-proof standard connector when we can now make individual components have their own protection for beginners just playing around!

A better modular system, I think, would be a set of standard, breadboardable modules, each with a defined interface number and spec, like OOP classes.

There's the #12 power supply module, the #8 current switch, the #4 USB port breakout, and the #17 controller module. Plug them all together on your breadboard and you're done.

You still get the fun of actually being able to build something semi-freeform, with only a little extra chance of messing stuff up, if the parts themselves all have some protection built in.

Or, plug them all into a PCB made for those specific standard pieces, and you have a finished product. You could even make separate education and production versions, without the same level of protection against shorting inputs and stuff.

But right now, the big thing is plug-together modules, which are awesome for what they do, and completely random nonstandard breadboardable modules(Every 4 pin I2C a different pin out!) with no protected version available.

I see some cool projects done with things like STEMMA, but it's only slowly coming into it's own, and a lot of boards like the RasPi don't seem to think it's really important enough to bother adding. Some do, like the Uno Rev4, but still... You're more likely to see stuff plugged directly into the IO pins.

The modular stuff is just for a limited number of use cases.

Modular smartphones seen like kind of a dead end, other than maybe one day having the ability to add a single accessory as a case. Modular laptops seem to be doing OK.

Hobby electronics is trying... and it's awesome... But we're not quite to the point of seeing commercial-quality modular OSHW for random gadgets, and I think we probably could be with a pretty reasonable effort, and the current crop of modular kits for beginner could be a lot more awesome at the same price.