I'm sympathetic to this POV. I think specifically in the case of Slack, it's not their responsibility in a cosmic sense, but it is in line with the direction and general promise they've been making to customers since forever.

A major part of Slack's go-to-market strategy for as long as I can remember has been pushing Slack as more than a interface for talking with teammates, but as a unified interface for generally piloting your business. Slack has heavily pushed ideas like "SlackOps", they've had Slackbot in the product forever, and they've always prioritized and sold integrations designed to let you build your business workflows in Slack. They even updated Slackbot to go from "that chatbot you DM to set reminders" to "Your AI teammate in Slack": https://slack.com/features/slackbot

So adapting to agents is in keeping with what Slack promises its users. I know that a lot of people don't want more AI features in apps that don't need them (i fall into this camp despite working in ML myself and using LLMs all day). I just think that in the case of Slack, their most passionate power-users are also the sort of people who do really want AI features.

Notion is probably a good companion here. It is similarly a really primitive utility--text editing--that has marketed itself as a sort of central interface for running your company. I know plenty of people, especially outside of engineering, for whom Notion is essentially their browser for work. And it's probably not a coincidence that the Notion + Slack are the two normal office software companies I can think of who've most heavily adopted and marketed AI features.