>As I’ve gotten a bit older and gained more experience, I’ve found that valuable startup ideas aren’t actually a scarce resource. In fact, they’re only becoming more abundant — as the world moves faster and more new businesses are created, more novel niches appear for profitable, productive companies.

If we define valuable as "profitable, productive companies" then I very much agree that there are plenty of niches out there.

However, if we are talking about startups that can actually grow big by Silicon Valley standards, I have personally come to the opposite conclusion. Ideas with the potential to become big are very much THE scarce resource.

I used to think that things like capital and teams are scarce, but it turns out there are a lot of sharp hard-working people with access to cash. By contrast, ideas that can grow to a billion dollar outcome are very few. I remember Andy Rachleff saying a decade ago that each year 10-15 companies are started that will eventually grow to become billion-dollar outcomes. My impression is that this pattern has held.

What does change all the time is where the opportunities are. Some industries mature, thus potentially closing for new opportunities, at least for a while, e.g. until a tech breakthrough. The good news is that new markets develop all the time, and the cycle repeats.

P.S. Thanks for putting this together and sharing with the community. I hope some dots get connected meaningfully.