As a german, working in the IT sector for a bit over 25 years I say: The alternatives are there, but the pain isn't hurting enough to finally force us out of the walled gardens.
It took me years to convince the company I work for to ditch big tech, and we are just a small (<50 employees) company.
On most of the clients we are now running OpenSUSE Leap, but for now we still need to run a few Windows boxes for our ERP system. Luckily, the next update of this system will make it browser based, so the clock for those system is ticking. Another thing that will keep two machines on Windows is the goddamn Datev...
For other tools we are now settled in on this solutions:
Paperless-NGX as document management solution
Seafile as cloud storage
Libreoffice as office suite
Thunderbird + Firefox as email / browser combo
Etherpad-lite and Ethercalc for collaborative editing needs