It's not an ageism problem, it's a loyalty and perception problem. Old people by their nature cling to institutions of loyalty and start-ups are definitely not known for staying around for +3 years.
Furthermore start-ups also implicitly prefer "just good enough" in order to get your company up and flying enough to quickly accrue investor interest, whereas stability forms the bottom-line of our elder engineers -- and stable systems require far more time than some investors are comfortable with.
Even worse, there is the management aspect. Older people have very different management styles, and throwing caution to the wind is definitely not among their managerial toolset. If your company has older people in positions of power then it definitely scares vast swaths of people away -- from eager investors looking to turn a quick buck and energetic young engineers looking to for autonomy to work without anyone second-guessing their decisions.
Finally, the saying "old is gold" applies quite well, however that gold needs regular polish to remain shining.
"Old people by their nature cling to institutions of loyalty"
You're a little out of date. That applies to the gold watch retirement crowd from WWII and "Mad Men" era and all that. None of those guys are under 80. The kind of people who think "talking pictures" on celluloid is high tech.
We are talking about (former) kids who listened to Nirvana on CDs while Kurt Cobain was still alive, not listened to Gunsmoke on the vacuum tube radio during the great depression LOL.
You say "it's not an ageism problem" but them go on to define an ageism problem. Your comment defines a stereotype of older people, claiming they cling to loyalty and have management styles incompatible with startup culture.
This simply isn't true. Some older developers have worked for Fortune 500 companies writing enterprise Java software for their entire careers. These developers often aren't right for a startup. But I've worked with teams of 100+ young (majority in their 20s) developers who can't think outside of Java + Apache + Tomcat + Waterfall world.
Age isn't a deciding factor for me when hiring someone. If a 65 year old developer approaches me with proven skills in multiple technologies (maybe node.js + scala + go), I really want to talk to this person.
Furthermore start-ups also implicitly prefer "just good enough" in order to get your company up and flying enough to quickly accrue investor interest, whereas stability forms the bottom-line of our elder engineers -- and stable systems require far more time than some investors are comfortable with.
Even worse, there is the management aspect. Older people have very different management styles, and throwing caution to the wind is definitely not among their managerial toolset. If your company has older people in positions of power then it definitely scares vast swaths of people away -- from eager investors looking to turn a quick buck and energetic young engineers looking to for autonomy to work without anyone second-guessing their decisions.
Finally, the saying "old is gold" applies quite well, however that gold needs regular polish to remain shining.