Yes, except for the fact that any non-trivial saas does non-trivial stuff that an agent will be able to call (as the 'secretary') while the user still has to pay the subscription to use.
Yes, but now it's easier for other SaaS to compete on that, because they don't get to bundle individual features under common webshit UI and restrict users to whatever flows the vendor supports. There will be pressure to provide more focused features, because their combining and UI chrome will be done by, or on the other side of, the AI agent.
That's the brilliance of AI - it doesn't matter if the product actually works or not. As long as it looks like it works and flatters the user enough, you get paid.
And if you build an AI interface to your product, you can make it not work in subtly the right ways that direct more money towards you. You can take advertising money to make the AI recommend certain products. You can make it give completely wrong answers to your competitors.
Will the SaaS also use LLMs? If so it opens the questions, why not and do we really need, as the article points out.
I don't think history opines favorably on companies that lose the last-mile connection with their customers.
For purposes of this thread, if chat AI becomes the primary business interface, then every service behind that becomes much easier to replace.