... Does it? The author made it pretty clear throughout the article that (in their opinion; see the "Blockchain" section) the walled-gardening comes from having

... Does it? The author made it pretty clear throughout the article that (in their opinion; see the "Blockchain" section) the walled-gardening comes from having to trap in your users in order to make some money from your service. The conclusion that you need to change the (larger picture) motivations for the existence of these services in order not to fall into this behaviour seems logical to me. (And, of course, if you want to change social organisation/motivation, the solution has to be political.)