The UK airspace structure will never change to the US one.
But you have mixed up en-route airspace with terminal airspace.
Shoreham does have ATC but the same scenario is played out at the many non-ATC airfields.
I understand you guys pay a landing fee which includes the navigation service fee?
because even if the airfield has CAS (Class D) the controller is still not going to provide "guaranteed" separation between VFR traffic.
Neither does the US and not all towered fields have radar, but in Class D at least traffic information is meant to be provided. And in my experience with the detail as 2 sheds has tried to highlight.
A factor contributing to the accident was the inadequate traffic advisory information provided by the controllers.