Yes, sandboxing is a technological protection, but once you have important data flowing we often don't have technological protections to prevent exfiltration and abuse. The global nature of the internet means that someone who publishes an app which abuses user expectations (e.g. uses accessibility to provide command and control to attackers) is often out of legal reach.

You also have so much grey area where things aren't actual illegal, such as gathering a massive amount of information on adults in the US via third party cookies and ubiquitous third party javascript.

Thats why platforms created in the internet age are much more opinionated on what API they provide to apps, much more stringent on sandboxing, and try to push software installation onto app stores which can restrict apps based on business policy, to go beyond technological and legal limitations.