I replaced a $120/year micro-SaaS in 20 minutes with LLM-generated code

I used to pay $120/year for a SaaS that hasn’t added new features in four years, and didn’t fix its broken billing system for three years. Using an LLM, I managed to rewrite all the functionality I used to pay for in 20 minutes. Is this bad news for “write once, don’t update later” SaaS?