For over a decade, the B2B SaaS playbook was beautifully predictable: flat, per-seat pricing matched with lucrative 80% gross margins. But the rise of autonomous AI agents has introduced a volatile variable cost—the Token Tax—that is silently crushing vendor economics and threatening to blow up enterprise budgets. If you are evaluating software portfolios or staring down an upcoming software renewal, you are no longer just buying software; you are reselling GPU power, and it's time to change how you negotiate.