I'm not a fan of this argument. We all build upon the work of those who came before us, and usually even the most blatant rip-offs add something.
I'd even argue the opposite: We should copy good ideas. There's no point in re-inventing the wheel over and over again. If we copy good ideas, we can build on them, and we can spend time inventing new things, rather than re-inventing everything just to make sure it's all original.
(And I say this as someone whose work has been shamelessly ripped off multiple times in the past.)
I think it’s unethical to copy an existing program’s features one by one, as precisely as possible
I'd argue that conceptually, TextMate borrowed at least as much from Emacs and BBEdit as ST did from TextMate.
After all, what was TextMate's raison d'être? It was not some totally new idea. It was a successful iteration of existing ideas. It was lightweight like a text editor, but highly extendable via scripting.
So, it was like Emacs, except not quite as infinitely extendable, but more friendly and had a native OSX GUI interface. And it was like BBEdit, except more extendable. (Correct me if I'm wrong on this -- I used BBEdit a bit back in the day but never dove too deeply into it)
ST iterated further upon TM's ideas and others. Yes, it implemented TM's bundles and syntaxes for compatibility reasons, which I would call a very good thing because why invent those wheels again. Any new entry into an existing software category certainly should leverage the existing ecosystem to the fullest extent possible, unless there is a very good reason not to.
It's been years since I used TM but I think ST's command palette was a big innovation over TM, and more keyboard-friendly. ST's integrated Package Control is also something I don't believe TM has an equivalent for. And ST is of course cross-platform: it's not like using TM is even an option if you're on Windows/Linux.
So I really reject the talk of ST being a "ripoff". Good software should borrow ideas and leverage existing work whenever possible. And it's demonstrably false to claim that ST offered nothing new, or that TM itself didn't borrow very heavily from other editors.
If you try ripping off large companies, you run the risk of getting sued. But if you do it to a 1-person company, you can generally get away with it. Still scummy.
> completely sensible decision
From a purely selfish “how can I profit without doing my own work” perspective, sure. Same is true of many types of unethical shortcuts in the world.
> ST's development has greatly outpaced TextMate
I haven’t looked in years, but when Sublime was about 4–5 years old (when I last spent some time examining it) this was nowhere close to true.
I would say instead that the man-on-the-street external impression of ST’s development has been faster.