The problem here is not the walling itself , it is lack of regulations over what they can, they cannot do. Which allows walled gardens to kick out apps they don

The problem here is not the walling itself , it is lack of regulations over what they can, they cannot do. Which allows walled gardens to kick out apps they don't like, impose all sorts of rules, and charge outrageously Developers associate the freedom of open standards and protocol to these abuses. In the early GNU years, the same philosophy applied to source availability. Closed source does make similar abuse fare more easier. Abuses can be prevented with well built regulation. Developers do not like to get into governance and policy so they want to solve it technically, Open Source or open protocols and standards etc, sometimes that opens up avenues vulnerabilities in design, which devs generally are tech savy enough to be immune to and come up with even more tech like https, adblockers hardware keys etc. This cat and mouse game leaves rest of the population far behind and vulnerable, sometimes you just have to do governance than look for pure tech solutions.