Having started 2 SaaS products in the past 9 years (1 exit and 1 profitable but nothing big), i would say definitely Yes. There are much less greenfield niches

Having started 2 SaaS products in the past 9 years (1 exit and 1 profitable but nothing big), i would say definitely Yes. There are much less greenfield niches available. All the low hanging fruit ideas are gone and the ideas left are much harder to execute on, and may not even yield the same ROI. In short, you need to work harder for lesser gain.