How big of a fuckup do we need to see to realize that running megabytes of arbitrary code from a dozen different domain for every website we visit is a bad idea

How big of a fuckup do we need to see to realize that running megabytes of arbitrary code from a dozen different domain for every website we visit is a bad idea? What needs happen for engineers to realize that process isolation is something that needs to be taken serious at the lowest possible level (hardware + OS), rather than through some magic abstraction layer (VMs, hypervisors, containers, etc).