I personally think Skype* is amongst the worst tools in the particular space. (Which is my personal opinion). I find that for messaging, Telegram and Slack work incredibly well. For conferencing, Zoom has a much better experience.
Teams is a confused product where messaging similar to slack is a goal, but it is confused with poor search and a UX based more around posts than conversations.
I'm having trouble parsing that, but am worried you may be suggesting parent's point - that Microsoft isn't releasing tools to run on GNU/Linux operating systems - is because not many enterprises run those OS's on the desktop?
Not that there's fewer free software options.
Also, the web version of Skype is relatively good now... not really excusing what MS has done, however may be better options.
The story has been for about 18 months that Teams is going to eat all the things, but the execution is slow coming.
And they're still not really doing it.
Skype for Business on Linux? Not happening. Good luck trying to install Linux on Surface Books/Laptops and the like without lots of screwing around as well -- and it probably still won't properly work.