Actually the WebAssist site does cover what you asked under the FAQ... there is a question that states: "If I cancel my subscription to the Extension Library, can I continue to use the products and premium content?"
The answer says, "No. Once your subscription ends you will no longer have access to the software."
Also keep in mind, WebAssist has stated that any code you have created - even after you cancel a subscription - WILL continue to work.
I don't think that is being blackmailed, personally... and anyone can still buy the extensions outright just like before if the subscription is not for them. Believe me, I debated which route to go as I already owned SuperSuite for some time... so I went back and took a look at all the products that WebAssist had released since I purchased and found that I purchased the majority of new products and major updates and found that the costs of buying all the new stuff each year (this is for my situation) would cost more than just keeping an annual subscription going.
Just some thoughts... hope you get it figured out for your situation.