Why marine attack helicopters follow existing aircraft families

Why did the US Marines use Sea Cobras while the Royal Navy adapted Lynx helicopters?

Each service built on an aircraft family it already supported: Huey commonality favored Sea Cobra, while Britain standardized around Lynx.

The US Marine Corps chose the Sea Cobra partly because it shared transmissions and other systems with the Huey family already in service. That commonality reduced the burden of introducing an attack helicopter. The Royal Navy instead standardized its amphibious aviation support around Lynx.