The author breaks down how large language models lower software development costs but don’t eliminate human-driven feedback loops and ongoing maintenance expenses. By comparing real-world SaaS prices (Jira at $400/month vs. Salesforce at $500/seat) to engineer-hour costs, he defines a “zone of viability” where buying remains cheaper than LLM-powered rebuilding. He frames his own project River against this threshold to gauge its business potential today.