One bad AI cold-email campaign can halve your whole company's email deliverability — your CEO's investor updates included. The part AI SDR vendors don't mention at renewal: since November 2025, Google stopped filtering non-compliant bulk email and started rejecting it outright. Microsoft enforces the same. Cross 0.3% spam complaints once and deliverability can fall 50% across every domain you send from. Recovery takes 3 to 12 months. Most autonomous AI SDR tools run their own sending infrastructure, so you get no visibility into your domain's reputation until the damage is done. This is the quiet reason the category implodes. 11x.ai, backed by $74M, lost 70-80% of its customers within months — ZoomInfo said it "performed significantly worse than their SDR employees." The whole autonomous-SDR market churns 50-70% a year, roughly double the humans it was meant to replace — because volume is the easy metric to show, so the tools optimize for it and quality collapses. And cost per held meeting exposes them: AI-booked meetings show 10-15 points less often than human-booked, so a $100 booking that holds 65% of the time really costs $154. The teams winning in 2026 aren't buying another platform. They're building outreach on their own top performers' writing, inside their existing CRM, with deliverability as a hard constraint from day one. If you run outbound: are you tracking cost per held meeting, or still reporting send volume and open rates? #AISalesEngineering #ColdEmail