2 years is actually fairly long in the startup world imo, most startups (by %) don't even last that long. The average across the SWE industry (not just startups) was hopping every ~2.5 years a few years ago, and I believe it's worse now. I only start to scrutinize if I see a pattern of several in a row of If anything, I tend to judge people a little bit who stay in the same place more than 3-4 years in this industry.…
While I completely understand this point of view, I wonder if you are speaking as an employer or employee? If, as an employer, how do you cope with your 25% of your staff leaving every year? How do you build that institutional deep knowledge if your longest serving person has I can really only view it from the view-point of an employer (so my comment comes from there.) Personally I've been in the same job for 33 years now (was my first job out of uni) but I've seen the company grow from 2 people to 50. Most of our staff have > 10 years with us, and a bunch > 20. They are highly skilled, and have a depth of knowledge about our products and customers that are unmatched. They earn salaries well higher than other companies would pay them.
50 people is of course very modest success - I'm not saying we're a unicorn, or even especially valuable. But from our view-point we're also not looking to hire folk who have short-term goals and are already looking for the next gig down the line. Obviously lots of job-hopping is a red flag for our recruitment process.
And that's the thing I guess. Another company would have a very different perspective, and be looking for a very different kind of person. And ultimately that's ok. We don't all need to fit the same mould.