The benefit of SaaS vs vibe coding all your own tools/apps is that the SaaS team will continue building and improving the software for you without you asking. If you try to vibe code each app in your tech stack you will have a hard time keeping all of the apps updated. What may kill or replace SaaS is when AI agents can replicate the concept of a dedicated team continually focused on improving a piece of software without you asking. The benefit of vibe coding is you can make exactly what you want for exactly your use case. Vs SaaS has to build one product for many (not as personalized). So the most likely outcome is hyper personalized + autonomously managed by AI. So instead of finding an app to use from a SaaS company, or vibe coding your own app but then being left to manage it forever, you will simply spin up your own mini SaaS company run by AI agents who will then build a SaaS for one (you) and continuously make it better based on customer feedback (you) and market changes (api updates, new trends, etc).