I am watching the market of notebooks offered without Windows in the German area since April 2016.
The same hardware is typical 130 EUR cheaper without Windows preinstalled.
I purchased May 2016 an Acer ES1-331-C0YK for 269 EUR
I purchased November 2016 an Acer ES1-331-P498 for 299 EUR
In January 2017 had been at economic 13" notebooks all major brands like Asus, Acer, hp, Lenovo listed
Suddenly in April 2017 all this offers disappeared.
I wrote special Acer Austria, they told me the Acer ES1-331 series is finished and the successor ES1-332 series will be delivered only with Windows preinstalled.
It seems Microsoft is begging for a new antitrust investigation and some hundred million EUR penalty.