However, I think you are mixing too many concerns into the same bag of problems. One problem space is software exploitation, which happens via missing access control or simply bugs. A sandbox can be made safe. VMs and hardware virtualization work. People just seem to use it in the wrong way, hence my initial proposal.
A second problem space is basically social engineering done by agents, which of course can't be solved by software alone. But this problem already exists today with humans doing this. Many fraud schemes work and are ran in company-scale manners. Agents will just do the same in an automated way. My initial comment doesn't propose a solution to that, and I think that is step two, after fixing that agents can hack arbitrary software systems, which is imho fixable to a sufficient degree. Once agents can't be "more criminal" than humans with criminal energy, the usual measures can be applied: police, legislation, education, etc. But that is imo independent of the software exploitation state of affairs we are in right now. We should not mix these two.
> People want tools that are able to connect to other resources.
I think you are misunderstanding my proposal. The architecture allows the agent to connect to resources. Just not directly, but via controlling e.g. a browser. The browser runs outside the agent's sandbox, potentially in another sandbox. The only API the agent can call within its sandbox is simple website interactions, like clicking or viewing the screen. It can click on links to navigate to a different website. It can read it via visually parsing screenshots of the viewport, but it can never read the source code, run JavaScript, or do arbitrary network requests (unless the website itself allows this, which is a security problem on its own and should be fixed/guarded). Also note that this would enable allowlisting or blocklisting websites. Native apps will be "connected to" in a similar fashion. Hence the "imitate remote controlling".