ST bootstrapped its ecosystem by directly and shamelessly cloning every one of its original features from the TextMate editor, and just copy/pasting its entire ecosystem, without contributing anything back. For years there was no special support for actually working on custom features from within Sublime Text, so if you wanted to create new language grammars or syntax highlighting modes etc. you needed to do it from within TextMate. Sublime users would come to the TextMate IRC channel to complain about particular language bundle features that were buggy in the not-quite-compatible environment of ST, and ask TM users to fix it for them. Kind of comical really.

Even still, TextMate is a substantially more carefully designed tool. My impression is that the Sublime programmer didn’t really understand the underlying philosophy behind many of the features he cloned, and kind of screwed up a bunch of the subtler details. (This isn’t really surprising; I’d say it pretty much always happens when anyone just copies something that exists; they seldom perfectly understand the context or ideas of the original creator, so the copy is always at least a bit degraded/distorted, with less clarity of vision.)

Sublime does have the advantage of working on more platforms though.