So many different functions. My company is purely cloud and we use Google as much as possible, but we still have tons as we need a help desk, a task board, HR software, credential management, Office for some people, Udemy, etc.
One, every subdivision of a company might have similar needs, but each one has niche table stakes that only one app provides. Case in point: Lawyers still use WordPerfect [1].
Two, and this is where I think Superpowered, the company in question, will stumble, is that every attempt to unify these disparate needs has ended up into a unholy giant mess of "Enterprisey" software that tries to be all things to all people. Inevitably there's at least one key area where it sucks to bad for the table stakes requirement of that user base that they never adopt it, strike out on their own, and now you're back to "why do we have so many apps?".
What's the alternative? You could try to centralize all of your apps onto Google or Microsoft or Zoho, but frankly if you want the best user experience, you have to work with several different companies.
Whilst I agree, that's an organizational problem as much as a technology one. Why is the business built upon so many apps?