I don't have any insights into how the company is doing, I'm just going by the sample set of people around me or things I read.

I'm a fan of indie software and native apps but I know zero people in the past 10 years that switched to ST. I know plenty of people of people who switched to Vscode and all the other free or paid competitors. It's probably enough to sustain a small company, and not everyone has to strive for a monopoly. But I wouldn't call that thriving.