Not sure how it would "lock out competition" when EA, Ubisoft, GOG, or any other distro platform - not to mention customers themselves - and even customers themselves - will be free to install whatever they want. Valve is on record that they will not prevent anyone from installing their own software.
I have not seen that but good if it is true.
My speculation was based on conjecture that many analysts were predicting. I hadn't seen an official stance from Valve.