At what point does SEO become a better lead gen channel than cold outreach for agencies?

I’ve been thinking about this a lot lately.

A lot of agencies still treat SEO like the long game they’ll “get to later,” while putting most of their effort into outbound, referrals, and paid acquisition. I get why — SEO takes time, and outreach gives you faster feedback.

But once SEO starts working, it feels like it compounds in a way most other channels don’t.

For those of you who’ve seen this from the inside:

• At what stage does SEO start outperforming cold outreach for agency lead gen?
• Are service pages still enough, or do you need strong supporting content to make the whole thing work?
• How much of the result really comes down to topical authority vs branded search vs links?
• Are most agencies underinvesting in SEO because it’s slower, or overestimating how much pipeline it can actually create?

Curious to hear from people who’ve actually used SEO to bring in clients, not just traffic.