Great points! I agree many SaaS products start simple. I gave an example of testimonial.to that might be at risk.

At the same time, most SaaS products evolve significantly over time.

We use them also because they offer pre-build, ready-to-use, and optimized UI, business logic, and workflows.

To replace them, you would have to design all that from scratch. That's a huge task.

Also, I don't believe the business logic will move entirely to the AI tier. This wouldn't be cost-effective. And you don't want to generate the UI on the fly every time.

So I'd rather expect you need to use an agent to build and then host and maintain an app yourself. This doesn't make sense if the cost of SaaS is low enough.

As I see it, the real threat to SaaS products that lack platform effects comes from new SaaS tools, not AI agents. AI might significantly lower the barrier to entry for creating new products.