Not so much dismissed as knowing they weren't ready. The ME-262 airframe was ready in 1938. It wasn't until 1944 that it had a working engine.
And those engines (when they had gas at all) ran only 20 hours between overhauls.
The British style of radial compressors was many times their reliability. (It took about a decade after the war to get Axial compressors running as effectively.