A matter of perspective. Everyone I have met with a cycle time of 1-2 years tends to be a low-value contributor. I get the feeling they move often because that's about how long it takes their team and management to conclude they aren't worth investing any more patience in. Some people only have interview skills.
But, I have not worked in a startup environment for almost 20 years so maybe in the right environment it is totally normal to expect people to jump around that often. I would advise being careful about keeping that up if you ever plan to move to a more stable part of the world because it is a stain on your resume.
> I get the feeling they move often because that's about how long it takes their team and management to conclude they aren't worth investing any more patience in.
Why would it take you 2 years to understand it about someone? In my experience, real figure is closer to something about 2 weeks.
In my experience people are pretty forgiving. At first you ascribe it to inexperience, unfamiliarity, etc. Eventually you decide maybe they just need to be coached because they seem otherwise competent. Then you put them on a plan. Then they leave before you drop the hammer. Maybe it doesn't take a full couple of years, but in a big company when you're busy with a lot of projects, it doesn't always move super fast. HR doesn't want us to fire someone because their is some risk and they know how much it costs to find someone new. My manager doesn't want me to fire someone unless they're truly irredeemable because there is no guarantee senior management will say yes to backfilling the position. It all adds up.
I haven't yet run across a valuable team member with a track record of short gigs, but I've run across several people who, in retrospect, clearly were just going from company to company in the area until they were too well known and then fled to another metro.
I can't speak for rootusrootus, but I suspect it may go like this: You figure out they aren't worth investing any more in, but they aren't worth the hassle and risk of firing. So you give them garbage raises. After a couple of years, they find greener grass somewhere, and move on.
> but they aren't worth the hassle and risk of firing
I'm so thankful that I'm living in one of the socialist european contries right now. Not being able to fire a bad contributor from my team would just make my blood boil.
But, I have not worked in a startup environment for almost 20 years so maybe in the right environment it is totally normal to expect people to jump around that often. I would advise being careful about keeping that up if you ever plan to move to a more stable part of the world because it is a stain on your resume.