Agents genuinely collapse the cost of code you own. Scaffolding components, wiring a data model, iterating on layout - work that took weeks now takes days, sometimes an afternoon. If you’re building on the right foundation, that’s a real, compounding advantage.
What agents don’t collapse is the cost of what you operate. Everything in the list above is an operational liability, not a code-generation problem. An agent can write a caching layer in minutes - but you’re the one on call for it. An agent can write row-level-security rules - but if they’re subtly wrong, the failure mode isn’t a bug, it’s a breach.
And agents add a requirement of their own. Once agents are changing configuration and querying customer data, “what happened, and was it allowed?” becomes a question your board asks. Auditability stops being a nice-to-have precisely when you start automating.
AI didn’t settle build vs buy. It moved the line - and raised the price of owning the wrong side of it.