...the rights to access and/or use any Content and Services accessible through Steam are referred to in this Agreement as "Subscriptions."
... The Content and Services are licensed, not sold. Your license confers no title or ownership in the Content and Services.
https://store.steampowered.com/subscriber_agreement
To me, that's their business if they want to operate that way and folks can choose to accept that and be a customer if they so desire. I think what's really wrong is that nowhere on their store pages do they use the word "Subscription" and instead they use the word "Purchase". This should not be allowed and is false advertising, plain and simple.