It's not.
The argument you're replying to is remarkably similar to the ones in the EU+Apple threads: Why should iOS be considered a "general purpose" OS? Because people consider it as such. Why isn't Xbox or Switch a "general purpose" computer? Because people don't consider it as such. The whole thing boils down to circular logic of "it is a general purpose computer because it is".
The same thing is happening here: Why is it ok to bundle Word and Excel, but not Word and Teams? Because people consider the first one ok, but not the second. Ok, but WHY?!?
It's like arguing with a religious fanatic. You are wrong to assume there is any logic behind it.
If you really dig into why Microsoft and Apple, and why not Spotify and SAP, the only real answer is: because the EC defined the boundaries of the DMA to include the types of businesses that are run from America and exclude the types of businesses that are run from European. When you finally back them into a corner, the defenders of the DMA fall back to "well $AMERICAN_COMPANY is a gatekeeper, but $EURO_COMPANY is not a gatekeeper".
Spotify and SAP easily meet the quantitative thresholds that catch MS, Facebook and Apple, but the EC carefully defined that a "gatekeeper" belongs to certain categories of businesses (operating system, social media, etc.) and does not belong to certain other categories (music streaming, business software) so that it does not catch them. And as we saw with iPadOS, the quantitative thresholds don't even matter if the EC feels like ignoring them.
I don't see why Spotify is a gate keeper. You have e.g. Deezer or Apple Music and you can switch very easily.
I don't.
No more than I consider NetApp OS or OneFS general purpose, even though both are based/built on BSD (I've SSHed into OneFS CLI often in my last job)
At least with Apple/iOS (not sure about Android), phones and tablets were purposefully designed to be appliances from the very beginning.
Teams is a recent addition which is orthogonal and is a product from entirely another market where the competition has offerings without an office suite. Looking from there, MS uses unrelated offering to hide the price of their product while pushing it to hundreds of millions who are already their clients.
Outlook is probably the most widely used, and again, if outlook can be considered part of the office suite, which it has been for decades, why not another communication software?
My broader point being these groupings are all pretty arbitrary.
Microsoft has always sold a cheaper "office suite" without outlook. What businesses have historically bundled and not bundled is irrelevant to what is best for society going forward.
Surely there were many features that many software businesses add that weren't there before. What if Microsoft relabeled Teams to be part of Outlook? Like they made Calendars part of Outlook. It all feels like starting at the result and working backwards towards a justification.
Being around for a long time is a quality of its own. It strongly implies familiarity and good enough fit for everybody. (Traditions compete in a sense, some do not survive)
My own company uses office 365, and of all the included programs, I basically only use excel, outlook, and teams. I haven’t even opened word in years, all documents are shared as PDFs. As such, word has no more inherent need for “bundling” than teams.
It just seems arbitrary. I’d be more comfortable just stating that companies over a certain size can’t bundle at all.
Suddenly, you are the loser, while they are selling below investment cost to simply push you out of the market.
So that's the issue.
Similarly, it should probably be made illegal for VC-backed startups to undercut incumbents just to shut them down: that's very similar to me.