What do you mean "stoop so low"? That's how it's always been in every other industry --- people can and do modify and fix things by learning how they work, without any form of assistance from the original manufacturer. I don't need to have the original design documentation to make or modify a new part for my car, boat, washing machine, HVAC system, etc. Why should software be any different?
But for a program to be free software, the ability to study and modify the program must be practical, legal is not enough.
It already is practical. As I mentioned, decompilers are only getting better and what we have now is far better than in the early days when people did "study and modify" just fine. I could also argue that a lot of current free software is not practical to "study and modify" even with the source code.
Instead, the emphasis on source code has created a sort of learned helplessness (see above) that is definitely an impediment to true freedom. Companies have instead used "open source" as a form of virtue-signaling while adapting other user-hostile "security" features that make it so users can see the source and try to contribute to it (with their contributions only accepted if they toe the line) but can't actually make use of those changes themselves. Android, Firefox, and some other Google projects come to mind.
Well, one reason the analogy is bad is the HVAC industry does not have the luxury of copyright in the first place. They have to rely on patents and trade secrets. The whole GPL concept is hinged on and is a hack on copyright and would be rendered moot absent copyright.
As a practical matter, it's hard to come by software that comes as a freely licensed binary but lacks source code. I'm blanking out on coming up with even a single example.
Re the ability of "study and modify" it does not have to be universal obviously. If a subset of community can do so the rest can benefit by their improvements passively, asking their help or contracting them.
But for a program to be free software, the ability to study and modify the program must be practical, legal is not enough.
It already is practical. As I mentioned, decompilers are only getting better and what we have now is far better than in the early days when people did "study and modify" just fine. I could also argue that a lot of current free software is not practical to "study and modify" even with the source code.
Instead, the emphasis on source code has created a sort of learned helplessness (see above) that is definitely an impediment to true freedom. Companies have instead used "open source" as a form of virtue-signaling while adapting other user-hostile "security" features that make it so users can see the source and try to contribute to it (with their contributions only accepted if they toe the line) but can't actually make use of those changes themselves. Android, Firefox, and some other Google projects come to mind.