The New SaaS Investment Thesis: What Changed from 2015 to 2025

The structural forces demand a complete reformulation of the SaaS investment thesis. What worked from 2015-2021 will destroy capital in 2025 and beyond.

The Old Thesis (2015-2021) — Dead

• Find product-market fit first, figure out unit economics later
• Grow fast — speed covers many sins
• Land in SMB, expand to enterprise over time
• Features create defensibility
• Sales teams scale everything
• NRR of 100%+ is acceptable
• Raise more capital to grow faster

The New Thesis (2025+) — Required

• Pick Floor or Ceiling from day one — There is no optionality premium. The middle is structurally unviable.
• Unit economics must work at Series A — If LTV:CAC doesn’t work by Series A, it won’t “grow into” working.
• Integration depth is the only moat — Features can be copied in days. Deep integrations cannot.
• Sales only works if LTV exceeds $500K — The math of enterprise sales requires high LTV to justify CAC.
• NRR must exceed 120% (Ceiling) or viral coefficient > 1 (Floor) — These are the only two growth engines that work.
• Capital efficiency from seed — Every round must demonstrate improving efficiency, not just growth.

The old thesis destroys capital in the current environment. Structural forces invalidate every assumption.

This is part of a comprehensive analysis. Read the full analysis on The Business Engineer.