Brian Balfour, Founder & CEO of Reforge and former VP of Growth at HubSpot, joins Mostly Growth to explore why product-market fit is a moving target. He introduces the concept of the Product-Market Fit Treadmill, a state where rising customer expectations and competitive pressure make it harder than ever to stay ahead. Brian breaks down how AI has accelerated PMF collapse, explains the hidden costs of product adoption, and shares how Reforge shipped five AI-native products with a team of just 20 people. Packed with frameworks, strategic insight, and startup realism, this episode is essential listening for product leaders, operators, and founders navigating the next wave of GTM.
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LINKS:
Mostly Metrics: https://www.mostlymetrics.com
CJ on LinkedIn: https://www.linkedin.com/in/cj-gustafson-13140948/
Growth Unhinged: https://www.growthunhinged.com/
Kyle on LinkedIn: https://www.linkedin.com/in/kyle-poyar/
Brian Balfour: brianbalfour.com
Brian on LinkedIn: https://www.linkedin.com/in/bbalfour/
Slacker Stuff: https://www.slackerstuff.com/
Ben on LinkedIn: https://www.linkedin.com/in/slackerstuff/
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RELATED EPISODES:
When the marketing math doesn’t math | with Emily Kramer
https://youtu.be/sSuoV_YSrlw
Why Founders Are Posting Sad Dinners
https://youtu.be/Zl6NSIHF2Gk
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TIMESTAMPS:
00:00:00 Preview and Intro
00:01:15 Sponsors – Pulley, Metronome
00:03:36 Guest Introduction – Brian Balfour
00:06:24 Writing, Frameworks, and Career Foundations
00:09:56 PMF Misconceptions and the Treadmill
00:13:25 AI Acceleration and PMF Threshold Shifts
00:16:07 CRM Expectations and Changing Market Dynamics
00:18:53 AI-Native CRM Approaches and Workflow Changes
00:21:08 R&D Investment and Customer Expectations
00:23:37 Roadmaps, Feature Velocity, and Customer Education
00:26:02 AI Adoption Across Product Discovery, Delivery, and Adoption
00:27:17 Product Adoption Constraints and Human Bottlenecks
00:29:06 Platform Cycles and Distribution Shifts
00:31:05 Framework for Evaluating Platform Bets
00:33:20 Open–Close Platform Dynamics in AI
00:36:34 Emerging Platforms and Early Ecosystem Bets
00:39:10 AI Discovery Channels and Traffic Distribution
00:40:03 Distribution Shifts and OpenAI’s Multi-Channel Bets
00:41:15 Hiring, Resumes, and AI-Generated Applications
00:43:20 Note-Taking Apps, Market Size, and “Flintstoning”
00:46:06 Vertical AI Note-Taking and System-of-Record Paths
00:48:27 Gamma, Canva, and AI Presentation Tools
00:50:15 Onboarding Innovation with AI Agents
00:51:57 Closing Remarks and Outro
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SPONSORS:
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