I think it’s pretty predominant (and awful) with many young, first-time founders in their 20s.
Once founders hit their mid-’30s and/or have been at it for 4–5 years, it tends to fade away. As we scale and learn, we learn we need specialists. We need folks with domain expertise. We need managers who have at least managed a small team before. We learn we need all types to scale. We learn that wicked smart generalists who haven’t done it before are critical, but not necessarily the core hires you always want after employee 50–100 or so.
So if you are feeling age discrimination, yes it is real.
But especially in SaaS, there are plenty of startups founded by folks over 30–35. And startups that have been around for a few years, growing past $5m in ARR or so.
Go interview there.