What I believe makes the distinction between engineer and non-engineer in the software world so difficult to pin down is that software is so powerful that most non-engineers can end up easily doing engineer-level work.

For example, a mechanical engineer is someone that designs mechanical systems. In order to do that, they will need specialized and very expensive equipment, and the end result will be produced with machines costing hundreds of thousands or even millions of dollars. Designing a system and producing a single one-off artifact are two very different things, and that's why a lone craftsman in their shed cannot do actual engineering (outside of pen and paper mockups).

With software, otoh, it takes nothing to go from default nginx for serving your static personal website to an orchestrated cluster of containers and load balancers. The problem is that, for the latter, if you haven't got an engineer-like training, you will not be able to reason about the system, because you didn't really design it.

"For example, a mechanical engineer is someone that designs mechanical systems. In order to do that, they will need specialized and very expensive equipment, and the end result will be produced with machines costing hundreds of thousands or even millions of dollars."

Not really. The difficulty to manufacture something isn't tied to the ability to engineer it. In fact, good engineers try to make the item easier/cheaper to manufacture. Take the AK-47 vs the M-16 - one used more exotic (for the time) materials with a more expensive and involved production process. The other was made with looser tolerances out of cheap stamped steel and wood that could be cranked out quickly. Yet they were both (eventually) of similar effectiveness.

These days, we have CAD and 3D printing available to craftsmen. If you want to build it out of metal and make it reproducible, you can build and print the parts to create molds to cast them from. Same thing for people how have a lathe and/or milling machine. In some cases you can get them used for a few hundred dollars. Record your dimensions and process and you can crank out copies of items with great results - no engineering training needed.