> A program that you can run consists of a series of numbers whose meaning is obscure. No one, not even a good programmer, can easily change the numbers to make the program do something different.

Source: https://www.gnu.org/philosophy/shouldbefree.en.html

Back in the old days, we only needed a hex editor and disassembler, maybe sometimes a debugger, to "make the program do something different".

PC magazines would publish binary patches too.

IDA showed up sometime in the 90s but it was extremely expensive, and cracking it became a "rite of passage".

Now, Ghidra is free and there are tons of other tools available.

I would say it was clear you had zero experience writing for a general audience if I wished to make unfounded assumptions like you.

You overlooked he wrote easily maybe? Cracking IDA was a rite of passage because it demonstrated skill.

The answer is: because modifying software without the source code (i.e. reverse-engineering) is extremely difficult.

I've had many experiences where the source code was available, yet finding what to change and figuring out how to rebuild the whole thing --- but without changing anything else --- was far more difficult than patching a few bytes in the binary.

To quote the title of this article, "open-source is just that".