This is exactly why Spotify can decay so badly and still succeed. This is why most widely-used apps are so bloated and offer such ridiculously bad UX. It's because the whole point of the business behind them is to ensure there will be no alternative.
Slack, Teams, Discord, et al. live off network effects. You'll go where the community is. At work, you'll use what your employer picks for you, and your employer has a huge list of concerns[0] that are more important to them than user experience. Spotify survives because of the catalog - making a streaming app is relatively trivial; reproducing all the deals with labels and individual artists is an insurmountable barrier. Netflix was untouchable up until their distribution deals expired, at which point the owners of the content all spun up their own streaming services - but a random entrepreneur can't possibly break into that market.
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[0] - Ranging from "does it tick the right cybersecurity questionnaire checkboxes", through "does it integrate with our SSO", "does it work with our SharePoint", to "was the golfing with the salesperson fun".