Why treaties ended the armored-cruiser successor

Did wartime armored-cruiser losses cause the Royal Navy to abandon the type?

No. Treaty limits prevented a successor even though battlecruisers were too large and ordinary cruisers too small to fill the old armored-cruiser role completely.

The wartime losses of Good Hope, Monmouth, Defence, and Black Prince did not by themselves erase the requirement for a large cruiser. Battlecruisers had grown beyond 40,000 tons and were too expensive to provide in the numbers once associated with armored cruisers. Light and treaty heavy cruisers could not fully replace their endurance, protection, and independent presence. The treaty system, rather than combat reputation alone, prevented a direct successor even while the operational gap remained.