Does somebody work 35 years in same company, it is usually 2-5 years -> new company grind rather than working at same company.
A few times in my career I've seen people with a decade-plus experience leave companies they would have stayed at for another two decades if it were within their control. It's sad. They struggle a bit because they often realise that they've over fit their skillsets to that single company.
One guy I knew was hired as a "web developer" in ~2005 because of his HTML/CSS knowledge. He continued to do basically just HTML/CSS until he lost his job in 2020. Lovely guy, but he saw his job as just a job and couldn't give a damn about learning new technologies. I often wonder what he's doing now... I doubt just knowing HTML/CSS is a hireable skillset anymore.
Context is always important.
What's weird about that? It's how things work in every other sector, why would our sector be any different?
I wouldn't want to be stuck in the same position for decades, but that's different than being at the same company for decades. If I found a company that treated me right, paid me enough not to worry about money, and allowed me to progress internally (at a reasonable place), I wouldn't complain.
That said, it is a red flag for me if most people in the team have been there for very long: it means that as a new comer I will always be bottom of the pile and have no career growth opportunity.