I'm not saying the assumption is fair, and there are certainly exemptions. I'm saying that startups tend to assume that if you've been at the same place for 25 years, there is a reason for that, and the reason is usually negative.
When you say 'people like me', keep in mind that just because you have had three different roles at one company in itself doesn't mean you didn't stagnate, just as the person with ten jobs may have stagnated.
All assumptions have some danger, and I'm not condoning the behavior. I think it's valuable to explain to people who feel they are being discriminated against based on age may be more likely associated with stagnation (actual or assumed) based on extended tenure.
I'm certainly not saying that someone who has held multiple positions has not stagnated, either, simply that fundamentally the only difference between me and someone who worked for three different companies but had the same roles as I did is merely the company nameplate. To make different assumptions based solely on that is illogical.
It's quasi-ageism, I guess, in that junior level workers are difficult to accuse of stagnation. So although junior level workers may stagnate, it may be assumed that they didn't yet. I've seen devs in their early 30s as victims of this stagnation assumption (10 years in some traditional industry).
When you say 'people like me', keep in mind that just because you have had three different roles at one company in itself doesn't mean you didn't stagnate, just as the person with ten jobs may have stagnated.
All assumptions have some danger, and I'm not condoning the behavior. I think it's valuable to explain to people who feel they are being discriminated against based on age may be more likely associated with stagnation (actual or assumed) based on extended tenure.