Yes — Keynesianism in its traditional form does tend to struggle with supply-side shocks, and the reasons have to do with both its intellectual roots and its policy tools.

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1. Why Keynesianism is less suited to supply shocks

a. Original focus on demand shortfalls

• Keynes’ General Theory (1936) emerged from the Great Depression, a period of excess capacity and insufficient aggregate demand, not from a world of tight resources.

• The policy prescriptions — fiscal stimulus, monetary easing — are designed to boost demand when idle labor and capital exist.

b. The nature of supply-side shocks

• A supply shock (e.g. an oil embargo, crop failure, sudden drop in productive capacity) reduces the economy’s potential output.

• This leads to stagflation — rising prices and falling output.

• Stimulating demand in such a context risks worsening inflation without restoring lost production.

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2. The inflation problem

Under a supply shock:

• Aggregate supply curve shifts left → higher prices at every level of output.

• Traditional Keynesian stimulus moves the aggregate demand curve right, which:

  • Raises prices even more.

  • Does not fix the underlying shortage of goods or productive inputs.

This is why 1970s oil shocks confounded policymakers who were using Keynesian models — inflation persisted despite high unemployment, something the old Phillips Curve trade-off didn’t predict well.

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3. Later adaptations

• New Keynesian models now integrate expectations, supply-side rigidities, and shocks into their framework.

• Policymakers learned that in a supply shock, the Keynesian playbook must be modified:

  • Sometimes tightening demand is needed to contain inflation.

  • Supply-side measures (investment incentives, deregulation, resource reallocation) may be more appropriate.

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In short:
Classical Keynesianism is optimized for demand-driven recessions. It struggles with supply shocks because its main lever — boosting demand — does not restore lost productive capacity and can accelerate inflation. This mismatch became historically visible in the stagflation era.

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If you want, I can map out exactly how the AD–AS curves behave differently under a demand shock vs a supply shock in a Keynesian framework, so you can see the structural problem.