I disagree. This has both APIs as well as connectors. One of the reasons I use Google Workspace as SaaS is because of the extensive API, that gives me the flexibility I need with a great starting point (and continued development, that I continue to benefit from).
Yes, but imagine a chat app that's designed for accountants, that has widgets for accounting, and it's set up for accounting workflows. That's _HUGE_ but not something that a "one chat to rule them all" is going to just go and do. You could use that same example for lab technicians and any other role.
I don't think that comparison holds, search is a task you do as part of a workflow, there isn't a big difference in search across verticals other than curation of the data set you're searching from. If chat is becoming how people do their work, I don't see how product proliferation across verticals isn't going to be a thing.
That's only obvious in hindsight. Back in the day, people said how in the world am I going to use the same search box for buying a car (color, make, model, photos) as I do for finding the latest concerts in my area (map, seating charts, etc.)
And you're right vertical SaaS DID become a thing, and so will vertical AI, but the horizontal versions of both (search and SaaS) crush the vertical ones (Google for search Microsoft for SaaS), and I believe it will be the same. Theres a layer above what you are talking about (e.g. Teams as the product vs Slack as the company).
Horizontal has a higher TAM and Vertical is easier to execute.
But this is besides the point. My point was that productivity is a minority of the TAM.